As suggested select Safe Mode - if operation Ok - a driver is at fault.
BTW - have you considered System Restore?


"Gb" <Gb@discussions.microsoft.com> wrote in message
news:89F7F865-EBF1-4DFB-845F-E46024349889@microsoft.com...
> Hi
>
> My XP Pro is locking up. Computer boots up fine and desktop loads ok.
> However after about a minute, whole screen locks and no windows or
> programs
> will open, mouse stills moves, clock stops. I have reinstalled XP and
> repaired, but no joy. Everything was fine until last week. I think it
> might
> be a virus, but I can't even get the anti-virus program to run. Can anyone
> help?