My computer shuts down after about 3 mins?

When was it built?

Which Zalman 750W psu?

What mobo?

What OS? Fresh install or not? If not, where did the OS come from?

Did it ever work without doing this?
- if yes, what did you do before this started?
- if no, follow the steps here:

http://www.tomshardware.co.uk/forum/page-261145_13_0.html

and let us know if anything different happens at any of the steps.

I tried those

Zalman 750W ZM750-HP Power Supply Mpdular SLI Quad +12V (ZM750-HP

EVGA X58 SLI LE Version - 141-BL-E757-TR (141-BL-E757-TR)

I built this computer yesterday and there is no OS installed

Now the moniter wont register at all.

When I start up the computer there is a long beep followed by 2 short beeps

One beep code table I found say for Award BIOS (which your board has), 1 long + 2 short beeps "Indicates a video error has occurred and the BIOS cannot initialize the video screen to display any additional information".

Check your manual, pages 33 and 66-72 for how to read 2-digit error codes on the mobo debug LED readout.

One thing to check: see manual p 52, configuring the initial video display. You must set here in the BIOS whether your video card in is a PCI or in a PCIEx slot. they are not the same - set it wrong and the BIOS cannot find your card.

13abie said:

I tried those

What happened when you cleared CMOS? How did you do it?