Whatever display you use, from time to time you probably find yourself squinting at it. In my case, realising I'm hunching over my desk usually prompts me to increase the onscreen type size or reach for my glasses.

Adjusting your sitting position and where your screen is in relation to the sun may help you view the screen properly. If there's too much glare, a screen filter can help. Adjusting the contrast is yet another option.

But none of this is much use if the fault lies with your eyesight or the hardware limitations of your monitor. Using a larger screen and switching to a lower resolution can help. If you've got a netbook, however, you'll already be using a low setting.

Microsoft's attempts to beautify the Windows interface can result in onscreen information being hard to make out - muted colours that lack contrast aren't ideal if you've got poor eyesight or are feeling tired.

Whatever your reason for needing a better display, we've got a host of tips to improve your viewing experience. Windows XP and Vista have built-in tools to help you overcome visibility issues, and we've uncovered some useful third-party tools. Reflecting the fact that there are useful onscreen tweaks to be made in both XP and Vista, we've provided advice for both versions of Windows.

Windows XP and Vista screen tips

Windows XP and Vista have dedicated menus to improve onscreen setup for impaired vision or use with a screen reader. In XP, go to Start, Control Panel, Accessibility. In Vista, go to Control Panel and click on the blue Ease of Access option.

Vista's menu has four main elements: a magnifier; a narrator (which starts automatically unless you click the Microsoft Narrator option and choose Exit); an onscreen keyboard; and a high-contrast display.

Ease of Access options

If you need help deciding which are most appropriate, ask for recommendations by clicking the option below the four icons.

Windows 7 will add accessibility support by extending its range of touchscreen controls; otherwise, all three versions of Windows cover the same basic options.

ClearType and font smoothing: Certain fonts are difficult to read. Windows has a tool to deal with this: ClearType. To activate ClearType, bring up the Properties dialog by right-clicking anywhere onscreen.

Under the Appearance tab, choose Effects, then tick the box next to ‘Use the following method to smooth edges of screen fonts'. Switch from Standard to ClearType on the now-active drop-down menu. You can also select the ‘Use large icons' option on the same Effects pane before hitting Apply to activate your chosen settings.

Another way to get a larger view of things is by choosing ‘Extra large icons' in the drop-down menu in the Appearance dialog. If it's helpful, you can set up your applications so that features listings and filenames are displayed larger.

Choose 'Extra large icons'

In Vista, right-click anywhere on the desktop, choose Personalize and select ‘Adjust font size' from the lefthand pane.

Depending on how many programs you've installed and how many are listed onscreen at once, you may find you need to fine-tune resolution settings, icon sizes and the way information is presented in order to get everything in view at once. You'll find that it pays to assess which programs are listed by default on the Start menu and under the recent applications menu.

If you can launch the most commonly used programs simply by clicking on the Start button and bringing up their shortcut, day-to-day navigation and use will be that much more efficient.

Using Window's accessibility tools: Windows' accessibility tools enable you to set up your desktop the way you like it - which may be different from the way your other half or your children like to work. The beauty of having separate user accounts is you can all have things your own way.

However, if you're not bothered about creating separate user profiles and are happy to occasionally adjust accessibility options, you can simply set Windows to wait a certain time and then revert to its regular setup.

On the other hand, it may be that you need to be able to use a PC in a specific way but don't always use the same machine. You can save your preferred settings and export them for use on another PC by following the prompts of the Accessibility wizard.

Magnifying information: Windows has a magnifier, which you'll find under Start, All Programs, Accessories in XP or in Vista's Ease of Access menu. It doubles the size of everything onscreen by default, but you can boost this to as much as nine times.

It's also possible to adjust how much of the split screen is magnified and how much is shown at standard size by dragging the divider between the two. It's best to retain a reasonable onscreen area for the original-size window or dialog as a marker when you scroll around your documents or desktop.

Mousing around: Many of us complain of the frustration of losing track of the mouse. These pesky rodents seem to have minds of their own. But it's possible to stop yours running off with such alacrity by adjusting the rate at which it travels across your screen.

To do this, go to Control Panel and choose the green Accessibility options icon. Under the Mouse pane you can set how quickly the mouse responds to being pushed around, and you can also tick the MouseKey option to unlock further features.

Keep control of your mouse

MouseKeys let you use the numeric keypad to the right of your keyboard to control your mouse or another type of input device. This is a useful provision for those with physical impairments that mean a joystick, paddle or single-handed controller is a more appropriate form of input.

StickyKeys: If you find it difficult to use a keyboard, particularly when you're required to press more than one key at once, try using StickyKeys. Accessed via Control Panel, Accessibility Options, this lets you press one of the ‘command' keys separately from the keystroke it's modifying.

Say you want to insert the £ sign, which you would normally do by pressing Shift and 3. Instead, you could invoke the StickyKey feature by pressing the Shift button five times in succession. Now you can press Shift and then the key you want it to modify, without having to press both at once.

ToggleKeys is another useful feature. It alerts you whenever you select (intentionally or otherwise) the Number Lock, Scroll Lock or Caps Lock.

Accessibility for the partially sighted: If you have difficulty reading information onscreen, you may find a screen reader helpful. Jaws is a decent choice.

The standard version of Jaws uses a speech engine to render written text as synthesised spoken text. The company also produces a version for Braille readers.

Viewing options in XP

Adjusting colour contrasts: Long- and short-sighted people are well catered for by Windows, but they're not the only ones: there are also good options for the colour-blind.

The popular belief is that colour blindness means you see even the most vibrant, multicoloured images in black, white and shades of grey. This isn't so. Many of us struggle to distinguish between certain colours - we're not just talking about whether those dark blue trousers are actually black, but whether you can see that the two or more colours in question differ at all.

Windows contains a preset list of colour combinations that will help with this problem. In XP, visit the Control Panel and select the Accessibility Options icon. In Vista, click ‘Set up High Contrast' in the Ease of Access menu.

Aid visibility with High Contrast

Voice recognition: Windows' default Sam Narrator is useful but quite basic. If you want to dispense with using your keyboard as far as possible, load up a voice-recognition package instead. Nuance's Dragon NaturallySpeaking is one of the best. You need to spend a bit of time training it to understand the idiosyncracies and unique inflections of your speech, but it's far more accurate than you might expect.

If you aren't keen on purchasing the software, you may find Microsoft Word's built-in utility sufficient. This can be used to read typed documents, but it's unlikely to be installed by default. To use it, go to Tools, Speech and have your Windows CD to hand.

Use Microsoft Sam to type up documents using speech

Get a better view of the web

The web has become an invaluable information resource, but it's grown up organically according to people's whims and interests - and this applies to both content and design.

Clever Flash animations, in particular, can be a problem for those with poor eyesight. Neither do they lend themselves to screen-reader use, since Flash pages are generally recognised by web browsers as graphics rather than separate text and image elements.

Similarly, since the creation of web pages relies on a set of guidelines rather than hard and fast rules, not all are as carefully constructed as they might be. In theory, all elements should be clearly labelled in the HTML source code. A table comparing the costs of different brands of digital cameras, for example, would be labelled ‘digital camera comparison table' and any images illustrating them ought to be labelled with the camera names.

Websites properly coded and labelled in this way are far easier for those with visual impairments to navigate - a screen reader such as Jaws will be able to read information enclosed in its Alt tags.

Web graphics can be a pain as they take ages to load up, particularly if you're hobbled by a slow internet connection. It's possible to dispense with them using the Internet Options dialogs in Internet Explorer (IE). This will ensure web pages load far more quickly.

You'll also find some websites, such as news.bbc.co.uk, have an option to show text only. Look for a button on the website's navigation bar offering a ‘Low Graphics version' or similar.

Look for 'low graphics' versions of websites

Online fonts and colour schemes: While your PC is capable of generating thousands of colours, the web has a fixed colour palette limited to just 256 ‘web safe' shades for the sake of consistency. If distinguishing between colours is a problem for you, it may be worthwhile telling your web browser which combinations you're most comfortable with.

In IE you can change a range of display settings using the Tools drop-down menu. Choose Internet Options, Colors or Accessibility to bring up the relevant options. Deselect ‘Use Windows colors' to specify your own palette. In the pane to the right of this option you'll see you can also set the colours to indicate whether you've already or have yet to follow a link.

Choose web display colours you're comfortable with

To simply view the information found on websites with greater ease, go to IE's View menu and choose a more appropriate text size. You may also find it helpful to view web pages using the Full Screen option (press F11 or go to View, Full Screen).

Audio options: Because computer use is largely a visual experience, there are few specific audio accessibility options built into Windows - although you can, of course, alter volume settings at will. To alter general sound output levels to suit, go to Start, Control Panel, Sounds, Speech and Audio Devices and choose Adjust the System Volume.

To make global changes to the volume at which your PC alerts you to important events (and the not so important events, such as the fact your three-page document has been successfully sent to the printer), choose ‘Change sound scheme' instead.

If you wish, you can add the volume controller to your Taskbar so it's available whenever you wish.

SoundSentry: SoundSentry does pretty much what you'd guess from its name: it keeps an eye out for specific events or actions and audibly lets you know about them as and when they occur. As with Windows' other Accessibility options, SoundSentry is customisable and can be set to alert you to as many or as few actions as you wish, ranging from new email and instant messages to the opening and closing of programs and documents and Windows exiting and shutting down.

Alternatively, if you simply dislike the standard noise Windows makes when performing routine tasks such as these, you can alter the type of sound associated with each action as well as setting your preferred volume.

For those who feel like they spend half their time firing up and powering down Windows, it could be a real boon to get rid of the regular refrain Microsoft has programmed into XP's startup routine. Then you can replace it with something less, well, like the sound of Windows booting up.

Handily, you don't need to override your PC's existing audio settings in order to make use of SoundSentry. You can save the default setup by giving it a name and create new audio profiles that can be invoked as and when you need them.

Another useful option is to get Windows to give you a running commentary using the Narrator. This reads out all information that appears in menus and dialog boxes onscreen. It also gives a verbal report when you select an option or need to know which ones are currently available to you.

You can specify the volume and speed at which the Narrator provides this feedback using the Narrator's Voice submenu.

Virtual keyboard: Windows contains a virtual keyboard which you can control by using the mouse cursor. Launch it from the Accessibility menu (under Start, All Programs, Accessories) and then choose whether to keep the familiar qwerty staggered key arrangement or swap to a ‘block' layout instead.

Use a virtual keyboard to aid input

If you find it easier, you can get Windows to recognise your keystrokes by merely hovering over characters rather than depressing them. The Typing Mode pane for input selection can be found under Settings on the onscreen keyboard.

You needn't click to type - just hover the mouse over a particular key

Alternative keyboard layouts: Making your machine accessible and tailoring its setup specifically to your unique needs can also be approached in a more fundamental way. You could invest in a more comfortable, forgiving keyboard, for example, or a mouse that requires less physical movement.

Optical mice with a suspended ball allow you to simply run the palm of your hand over the top, saving your fingers from taking the strain. Other models can be programmed with shortcuts to provide single-click access to your email client and web browser, for example, or will happily launch a new Microsoft Word or Excel document.

Some people find split keyboards easier to use and less of a strain on the limbs. Both Microsoft and Logitech produce a range of such peripherals.

Do you spend a lot of time typing away and getting frustrated by the hobbling, counterintuitive qwerty keyboard layout? The qwerty layout, indeed, was designed specifically to slow down typists: 1920s typing-pool ladies were clattering their manual typewriter keys, causing them to clash and tangle.

The Dvorak layout may be a better alternative. XP supports this; it can be downloaded from microsoft.com/enable. What you do about relabelling the keys is another matter, however.

You can buy a dedicated Dvorak keyboard without breaking the bank, but a common strategy is to rearrange the keys yourself. If this sounds like a good idea, just remember the time you tried it with a Rubik's Cube: the puzzle was never the same again, and the loose pieces were always a bit of a giveaway.