As the furore over Vista's failings and the cries for Microsoft to continue to support XP has shown, it matters what operating system (OS) you run. Some people like to keep their options open, however, by maintaining multiple PCs - the average PC Advisor reader's household has at least three. Some of you even admit to giving houseroom to a Mac.

But it's not just a matter of wanting to enjoy a variety of computing experiences that may lead you to experiment with a different OS, it's what that OS can do, how it behaves and the software it can run.

Perhaps you've just upgraded to Vista and found that some of your older software is no longer supported. Or maybe you've discovered an exciting new software package, only to find that it runs under Linux.

These are just two instances where you might want to run more than one OS, but you needn't buy two machines or set up a dual-boot to achieve this. Virtualisation is a much easier approach and, over the following pages, we'll show you how to use it.

Such software creates a ‘virtual' machine - a software emulation of a real PC. A virtual machine behaves exactly like a physical one, and you can install any OS you like on it. The only catch is that it must run on a PC.

Running a guest OS that's identical to the host OS might not seem particularly useful, but this technique adds security for those who use the same machine for both business and pleasure. For example, a virus, failed installation or corruption on the guest OS can't interfere with the host OS.

In the workshops that follow, we'll be using two virtualisation packages. We'll use Microsoft Virtual PC to run a second OS for which you have the disc (an older version of Windows, for example), and VMware Player to run a pre-prepared virtual machine of a free OS such as Linux.

Create a virtual machine with Microsoft Virtual PC 2007

1. Install Microsoft Virtual PC 2007. Officially, the program is supported only by XP Pro and the Enterprise, Ultimate and Business versions of Vista. If you try installing it under XP or Vista Home you'll get a warning message. Don't panic: it'll still work. Click ok to continue.

Microsoft Virtual PC 2007 - Step 1

2. Launch the program and the main console and a New Virtual Machine Wizard will appear. Since, as yet, no virtual machines exist, creating a new one is the only option available. If you're running the Home version of XP or Vista, you'll once again be warned that your OS isn't supported - just click ok.

Microsoft Virtual PC 2007 - Step 2

3. Click Next to progress to the Options window, then select ‘Create a Virtual Machine' and click Next again. You'll need to enter a name for your virtual machine - a sensible option would be the name of the OS that you intend to install in it, but choose what you like provided it's easy to remember. Click Next.

Microsoft Virtual PC 2007 - Step 3

4. Select the OS you intend to install from the drop-down menu. Click Next and, when the menu appears, you'll see a list of supported guest operating systems. If yours isn't in the list select Other. Most OSes that run on PC hardware can be installed under Virtual PC 2007, with the notable exception of Apple Mac OS.

Microsoft Virtual PC 2007 - Step 4

5. Virtual PC will now calculate how much virtual memory and how large a virtual hard disk your guest OS will require, then give you the option to increase that amount of memory. Unless you've a good reason to do otherwise, select ‘Using the recommended RAM' before clicking Next.

Microsoft Virtual PC 2007 - Step 5

6. Under ‘Virtual Hard Disk Options', select ‘A new virtual hard disk' and click Next. You must now either accept the default virtual hard-disk capacity offered, or allocate more space to the apps you're going to use and the amount of data you anticipate storing. Make your selection accordingly and click Next, then Finish.

Microsoft Virtual PC 2007 - Step 6

7. Insert the CD for the OS you'll be installing. When the Windows installation automatically starts up on your usual PC, end the process. On the Virtual PC console, which will now show your new virtual machine, click Start. The virtual machine will start up and the boot sequence menu will appear.

Microsoft Virtual PC 2007 - Step 7

8. The virtual machine will try (but fail) to boot. In the CD menu select ‘Use Physical Drive X:' (X being your drive letter), then select Reset in the Action menu to cause a reboot. The virtual machine will reboot from disc. Follow the onscreen instructions to install the OS on your virtual machine.

Microsoft Virtual PC 2007 - Step 8


Run a virtual appliance in VMware Player

1. Download and install VMware Player and the virtual appliance for Damn Small Linux (DSL). We've chosen DSL because, at 49MB, it's a small download. The process is much the same whichever virtual appliance you use, however.

VMware Player - Step 1

2. Start VMware Player. From the main interface click Commands, Open. Browse to the DSL file that you downloaded in step 1 and click ok. You'll now see the boot sequence start for your virtual appliance. After this, you'll be prompted to press Enter to begin or F2 and F3 for boot options.

VMware Player - Step 2

3. If you press Enter, nothing will happen. That's because input from the keyboard is currently directed to the host OS (Windows). Instead, press Ctrl, G to direct input to Damn Small Linux and press Enter. DSL will boot in the VMware window. This will start up the guest OS.

VMware Player - Step 3

4. Having pressed Ctrl, G (or clicked the mouse inside the VMware window) you'll no longer be able to move the mouse pointer outside that window - even to close the application window. To return to the host OS press Ctrl, Alt (there's a reminder of this in the bottom left of the window).

VMware Player - Step 4

5. Disc drives and peripherals can be connected only to one machine at a time, whether it's the physical machine running the host OS or the virtual machine running the guest OS. To switch between the OSes, use the Devices menu. Listed devices are ticked if the guest OS is connected - click to connect or disconnect a device.

VMware Player - Step 5

6. You can now start to get a feel for DSL. As you can see from the screenshot above, a handful of applications are bundled with the program. The setup procedure is much the same for whichever OS you download as a virtual appliance. You can even have multiple guest OSes running at once.

VMware Player - Step 6