Computer turns off shortly after turning on

[callumshell]

Well I recently bought a computer, specs below:

XFX 790i mobo
BFG 9800 GX2
Corsair 4GB RAM
Intel Q9450 (retail)
Hiper Power 850w
Windows Vista Home Premium 64bit (OEM)
80 GB hard drive (brand new)

But when I went to turn it on for the first time, it turned off about 20 seconds after. I tried again and again, with it sometime staying on for 1-2 mins. It managed to install windows in about half an hour, which I find very hard to believe.

So what's going on with my computer?

[Katreat]

You say bought, did you buy pre-built or build it yourslef?

Quick turnoffs often indicate a heating problem. Ususally on a new build the heatsink for the CPU is not fully seated. So the first thing I would do is double and triple check to be sure the heatsink is properly installed on the CPU.

If it stays on long enough you can also check this by getting temp readings in the bios, just turn it on and see if your temperatures are rising.

Kat