computer help

[Spudly]

well a friend of mine has been having some computer problems. when he starts his computer up, right before the log on screen pops up the computer just restarts and does it again....help?
hes got a compaq- p4, winxp, 2 sticks of 128 and one stick of 256, geforce 4 ti, unknow motherboard, sorry for the missing info...help me if you can thx
also i tried going into safe mode and it does the same thing

 

[LeeJend]

The first thing you have to do is go into the bios and change it from "reboot on error". That way a blue screen with error messages will pop up that helps diagnose the problem. Post the info from the blue screen after you do that.