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Windows 7 upgrade survival guide

Make migrating to the new OS painless

Many PC users trying to upgrade to Windows 7 have been presented with some serious bugs. However, we've got a few tips that will ensure your migration to the new OS goes smoothly.

Bad product key

You paid good money for your Windows 7 upgrade, but when you try to activate your new installation using the product key that came with the disc, you get an error stating that your product key is not valid. Unfortunately, the fix for this problem is easy but time-consuming. Here's how to cope with it.

This problem isn't so much a bug as it is a bit of unfriendly engineering. The invalid-product-key warning arises when you attempt to install an upgrade edition of Windows 7 on a drive that has been formatted.

You must install the upgrade edition on a PC that already has either Windows XP or Vista installed on it. If the setup routine fails to locate a previous installation of XP or Vista, Windows 7 thinks it's being installed on a new PC rather than as an upgrade. Therefore, your upgrade product key won't work.

To resolve this issue, you need to have either XP or Vista installed on your hard drive at boot time. That may very well mean digging out your old XP or Vista discs and performing a fresh installation of that version before trying again with Windows 7.

It's important to note that Windows 7 requires you to have Service Pack 1 installed on Vista, and Service Pack 3 installed on Windows XP. So be sure to run your automatic updates on the old OS before moving on to the Windows 7 upgrade.

If you have a backup of your XP or Vista system handy, the fastest fix may be to restore that backup to your hard drive and then try the Windows 7 upgrade again.

Once you've put XP or Vista back on your hard drive, boot from that drive and then insert your Windows 7 upgrade DVD.

You'll still have the option to perform a clean installation of Windows 7 on your system, if that's what you want to do. Just make sure that your primary hard drive has a qualifying previous version of Windows installed on it, and then boot from the Windows 7 DVD and select Custom (Advanced) as your installation type.

You can then format the drive using Windows 7, without encountering the invalid-product-key error at activation time.
In the event that the same activation error pops up after you've followed these instructions, your best bet is to activate Windows 7 by phone.

To do so, click Start, Computer, Properties, and choose Click here to activate Windows now.

Look for the option to activate by phone, dial the number the system provides, and follow the voice-guided instructions. In the worst-case scenario, a Microsoft support person will help you activate your licence.

Small business IT advice

See also: How to choose the right version of Windows 7

  1. We show you how to make migrating to the new OS as painless as possible
  2. Bad product key

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