You might want to try a Windows System Restore. In the US version of Windows XP (not sure about the UK version), Windows periodically creates restore points. You can reset your computer to the way it was at the time of any of these restore points.
Of course, if there is something physically wrong with your drive, Windows Restore won't fix that, but if it's corrupt software, then System Restore might work.
:::I think I put too many commas in that sentence
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