Hi I thought I' just post so if anybody else has this problem that it might help someone out. I posted about a week ago about my computer randomly rebooting and with the excellent advice from this forum I narrowed it down, I think, to the USB PS2 converter/pad I had plugged in on the USB2.0 socket on the back of my machine. I got an extra 1gb ddr400 pc3200 and installed it and my computer kept rebooting. I checked each stick of memory seperatly and all seemed OK. I then installed a mother board momitor and it seemed that my computer was overheating, so I took the fan and heat sink off and gave them a good clean. In the mean time I had unplugged the converter/pad to narrow down problems, as this is new aswell. My computer seemed to work fine with an idle temp of 47-50c and a gameplaying temp of 60-63c. I then plugged back in the converter/pad and within 10 minutes of playing Splinter Cell it rebooted. I unplugged it again and the computer seems fine!! What I think the problem is, is either a faulty USB socket or some kind of conflict, maybe with the new memory and the socket. I know the converter/pad is OK because I can plug it in the front and all is well. If anybody knows different I would be grateful to hear from you. Anyway I hope this helps somebody. Many thanks to all the people that posted, you have been a great help. I shall keep posting on this site and passing on my wisdom. LOL Long live Tech Forums!!!!!!