Please help, new machine shuts down!

[stimrob]

Hi guys im new here but im looking for an answer to a frustrating problem. I just built a computer and as soon as I power it on, it powers itself back off after 2 seconds. The HD\CD\fans all come on and spin, but it shuts down. Any help would be appreciated. My hardware specs are as follows :

SAMSUNG SpinPoint T Series HD501LJ 500GB 7200 RPM SATA 3.0Gb/s Hard Drive - OEM

AMD Athlon 64 X2 4800+ Brisbane 2.5GHz Socket AM2 Processor Model ADO4800DDBOX - Retail

ASUS M2N-SLI Deluxe Socket AM2 NVIDIA nForce 570 SLI MCP ATX AMD Motherboard - Retail
COOLMAX CUG-700B ATX 12V( V.2.2) 700W Power Supply - Retail

mushkin 4GB(2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Chennel Kit Desktop Memory Model 996557 - Retail

[dcc]

Did you apply thermal compound between the CPU and the heat sink?

[stimrob]

I did not, however the heatsink came with a pad on it, which I assume should be sufficient as the processor manual did not mention applying a heat compound. Do you think the problem could be with mis-matched ram? again i am a noob as this so any help you offer is absolutely appreciated.

[stimrob]

I did not, however the heatsink came with a pad on it, which I assume should be sufficient as the processor manual did not mention applying a heat compound. Do you think the problem could be with mis-matched ram? again i am a noob as this so any help you offer is absolutely appreciated.
If I remove the video card, the time that it takes to shut down shortens from 2-3 seconds to about 1 second, dont know if that helps.

[dcc]

My first thought was that the CPU was overheating and some first time builders don't apply thermal compound or not enough and the CPU overheats and shuts the computer down very quickly. If you have any doubts purchase some arctic silver and apply a small amount to the CPU. Do remove the pad first and clean the mating surfaces.

I doubt that your problem is you RAM. I would look to see if you have a short from the motherboard to the case. On the back side of the board you can see a solder pad around the mounting holes, these are the only areas that should be touching metal.

Another route to take would be to remove every thing from the motherboard but you CPU and heat sink and fan, and you PSU and turn it on, it your computer shuts down start looking for a short. If your computer doesn't shut down you should get some beeps for the failed POST, you should check you manual to be familiar with the different codes. Add you RAM next, and then you graphics card, usually adding the component one at a time like this will show what component you are having a problem with.

I know this is probably redundant, but go back and check all of your connections, check you header connections, make sure your RAM and cards are seated properly.