Computer keeps shutting off

[Shuesplace]

Well first of all i'll give up my system specs:

Mobo: Gigabyte S-series Model: GA-M55SLI-S4 rev.2.0 supports Amd Am2 duo
Processor: AMD Athlon 64 X2 Dual Core 4600+
Ram: Wintec 2x 512Mb DDR2 800 Mhz
1x Seagate SATA 320Gb HDD + 1x Seagate PATA 120Gb HDD
Video Card: Nvidia GForce 7300 GS
OS: Windows Xp Pro SP2

I just put this pc together myself(first build), and im having a problem, my pc keeps losing all power(it doesnt shut down, it shuts off). Its not the PSU, i've tried 4 different ones. Its not the cooling, i checked that and the temps are where they're supposed to be. I've tried using just one stick of ram and i've alternated them. I dont think it could be the OS b/c i booted it the other day and before i could get into the bios is shut off on me. I've checked every wire to make sure everything is plugged in completely, everything is up to date. I've probably torn this pc apart about 6 times already, trying to figure out whats wrong with it. I'm going out of my mind. Can anybody help me?! I'd very much appreciate it.

 

[beef_jerky4104]

Wintec is not a very popular brand, it could be corrupt. Attempt running memtest, that will prove if its the RAM or not. You said you tried different power supplies, how many watts were they?

P.S. I'm pretty sure you meant GeForce. And there is no such thing as an AMD Duo. Duo has to do with Intel's CPUs.

 

[Shuesplace]

ya i meant Geforce, i've used a 380 watt, 400 watt, 450 watt, and 500 watt

 

[Tedster]

provided your PSU is powerful enough, I would say it is your el cheapo ram.