I'm having a really wierd problem with my PC - I can't boot from cold, but I can boot if the system is restarting.
i.e.
If I shutdown, wait a few minutes, then turn on the PC, Windows XP gets to the Splash screen (before the login) then after a few seconds it reboots.
It then continues this loop for as long as I leave the PC on.

If I boot into Linux (gOS) first, then restart the PC from there, XP starts fine.
Equally, if XP is already running I can restart with no problem.

Any ideas what could be causing this?