Problem. My computer randomly re starts, mostly when browsing on the internet. When the PC restarts it starts normally with no messages or warnings while going back into windows. The PC is a new build as follows: Sempron 2300+ 400W PSU PC Chips mobo M851 ver 1.3a 512Mb DDR 400 On board graphics SCSI card CDRW DVD Floppy Win XP Pro After the PC was built I ran memtest and CPU stability test for 6 hours with no probs. All temps and voltages seem to be ok and no crashes or restarts. The only thing that has changed since running these tests is that the SCSI card now has an HP 4P scanner and a Zip drive attached and via a USB hub there is an HP 6p laser jet and a canon i9000 A3 printer. Also the PC is now attached to a different ADSL router (netgear) than the test set up (belkin). Could these additional devices, which are rarely used and never at the same time, be demanding too much power causing the re starts or is this more likely to be a software issue? I have heard that the HP 4P scanner struggles to work with XP however I loaded all the software and it works fine on this PC. Any help greatly appreciated.