Computer won't stay on long without shutting on?

I havereset ( as in take it out and put it back in) the video card. I also got some temps i think it might be the cpu not sure. Thecpufan ( i saw all the other fans work too)is working though cuz it was moving. I have a Corsair 750TX, GigaByte P45, Hd4890,Wd 320gb Hd, Q9400, 4gm Ram (corsair).. I turned on my computer on came the motherboard lights but no video card lights ( which was the normal way for me) so it looked fine i got temps and shut it off cuz i was scared of doing something. I took off the fan and check to see if the cpu was fried but it didn't look like it was nor smelled so im guessing its fine, http://img4.imageshack.us/gal.php?g=p1010309m.jpg Those are my temp that i got about a minute after i turned on the comp.

How do i know what's wrong and what should i do, i'm really scared , i've only had this omputer for 1 week and its my first computer over 256mb... my other computer doesn'twork and is 7yrs old..

Re-apply the CPU with some thermal paste and try taking out the GPU and re-inserting it.

Eliminate case clutter and get 80-120mm fans.

You're probably just exceeding your power supply by a whole lot. If your CPU was fried you wouldn't even get to the start menu. Try taking your video card out and then see if it turns on for a few hours without shutting off.

I'd hope so i had trouble applying it, i had the same problem first time to. There was still paste on the Cpu. And there are 3 fans in my case >.< . ANyone know a way to check cuz pushpins are annoying as hell;. And how do i check if my psu is screwed i got a multimeter

RedxSniper, what is your PSU's wattage? What parts do you have in your PC exactly.

Because alot of things can cause your PC to shut down randomly. Could be because of a cheap motherboard, Cheap RAM or a cheap heatsink. Did you make sure the Heatsink was attached properly? It could just be like I said an Inadquite power supply for the parts in your PC.