No idea whats wrong with my computer

[gard9070]

• Windows XP SP2 Not sure what version
• EVGA 122-CK-NF66-T1 LGA 775 NVIDIA nForce 650i Ultra ATX Intel Motherboard
• Intel Core2Duo E6750 Conroe 2.66 GHz Model BX80557E6750
• OCZ Platinum 2 x 1GB 240-Pin DDR2 800 (PC2 6400) Dual Channel Kit Model #: OCZ2P8002GK
• Foxconn FV-N79SM2D2-OC GeForce 7900GS 256MB 256-bit GDDR3 PCI Express x 16 SLI Supported
• Onboard Audio HDA 8 Channel
• ASUS WL-138g V2 PCI Wireless Adapter
• Western Digital Caviar SE16 WD5000AAKS 500GB 7200 RPM SATA 3.0Gb/s Hard Drive - OEM
• SAMSUNG 20X DVD±R DVD Burner Black SATA
  Model SH-S203B - OEM
• Sunbeam / CaseGears Black Steel 580W Power Supply
• Apevia X-Cruiser Thermally Advantaged Case - Black

So I turn my computer on and it turns on fine, then about 30 seconds later it shuts itself off, ive replaced the motherboard and the power supply, and it still hasnt been fixed i have no idea whats wrong with it. Earlier today i just put in the new power supply and it worked for about 30 minutes, then it shut off. I tried turning it back on but it stayed on for about 30 seconds then shut off again. Ive had this problem multiple times with multiple power supplies, so i know thats not the problem. Either is the motherboard, cause its been replaced.

 

[oriion]

Does your Mobo have on board video, and if so, have you tried using it instead of the video card?

 

[gard9070]

no it doesnt

 

[oriion]

My next course of action would be to test out the video card. I don't think it would be the RAM or hard drive.

 

[Teny]

why would it be the video card?

Im guessing that something is overheating. Go into your bios and check the temps.
Or try using 1 stick of ram and see if that works.

 

[gard9070]

ive tried just using the standard stuff needed in order to run you computer aka 1 stick of ram, video card, hard drive, and mobo...not even a mouse or a keyboard due to the fact that i thought the USB was shorting it out...but no...it still does it

 

[Teny]

is your computer short circuiting?

 

[99nasha]

Test the memory, reset the cmos, try and swap the graphics card, do a hard drive diagnostics, re-install windows.

I'm just grasping at straws here

 

[Remeniz]

Make sure the CPU heatsink is properly seated. And as suggested before, check your on board temps.

 

[mikee]

Make sure the CPU heatsink is properly seated. And as suggested before, check your on board temps.

yes definatly check that. It caused my computer to do the exact same thing. Of course reapply thermal compound too