Installation problem

[John Mackintosh]

I have just had to reinstall Windows XP Pro which installed
perfectly previously, but this time it installed perfectly up until
first bootup splash screen, as the small blue discs made a second
pass, then it froze.Tried a few more bootups but it froze every
time at the same position. Unistalled Win XP Pro and reinstalled,
with exactly the same problem. This is using the upgrade choice.
Any ideas please.
John.