:wave: Hello all u guyz, i'm noobie in this forum (I hope it's the proper place to post this thread...) Well, I built up a new pc days before. Pieces: Athlon64 3000+ 754socket GIGABYTE GA-K8NSNXP 754 Ram KINGSTON KVR400X64C3 512MB PC3200 400MHz (1 stick) Trust qtec power supplier 500W Seagate 200GB Barracuda sata the prob?Ok here it goes. I firstly tried to install winxp in the just-formatted HDD. I managed to do so, yet windows kept restarting all the time, esp. when i tried to run an application or a game. I firstly reformatted and tried to re-install winXp. But I couldn't, ethier because of the reboots my pc kept doing (in the middle of wins' setup!) or because receiving a blue screen saying there should a be a hardware or software prob, after which it needed to reboot.... I tried many times to install XP, I couldnt, so I tried to Install win2K. Not believing it, I managed to install them normally, but my pc keeps restarting in a way I can't do or play anything.....Any suggestions? I haven't run the memtest86 yet. If it is not a mem prob what could it be? Is there any possibility my power supplier cause this mess?