Had a virus called Vundo.P. PC kept rebooting randomly or perpetually. Virus was eventually removed not by Norton but by Stopzilla. Problem still persists. Have reformated hard drive added Norton antivirus, partitioned hardrive for storage purposes with Norton Partition Magic and all was fine. Turned PC off and back on next day but PC has gone back to random re-boots again. The PC is a home build and except for the power supply and hardrive all other components were purchased new last year and all has been fine up to recently. I am using Windows XP Home Edition with Service Pack 3. The cooling fan on the processor is working and clear of dust etc. Grateful for any ideas as to where to look as I'm scatching my head with this one. Many thanks.