First build - won't stay on

[bet4a]

I attempted to build my first PC this evening, but when the big moment came to turn it on for the first time, I was greeted with this infuriating problem. The front LEDs turn on and the fans (PSU, case and CPU) start spinning, but after a second or two, it shuts off. The exact amount of time it takes to shut off is variable, but never less than half a second and never more than wo seconds.

I've taken the motherboard out and reassembled the basic components out of the case, as described in HAL9000's post. No luck. The same thing happens when I attempt to boot the PC without the RAM or video card attached... after a second or two, everything shuts off.

I'm using an ASUS M2N-SLI Deluxe motherboard with an AMD Athlon 64 X2 5200+ CPU. I'm completely new to this, so I'm not sure how to figure out whether the problem is the CPU, motherboard, PSU, or something wrong that I'm doing. Any help will be greatly appreciated.

[LeftyAce]

Can you please list the full system specs, including the brand and wattage of the psu? I assume you've attached the cpu heatsink and fan as per the instructions?

Also, make sure you have a case speaker connected to the posts on the motherboard. Are there any beeps?

[bet4a]

Here's all the info (with links to the products on Newegg, where I got them all from):

Processor: AMD Athlon 64 X2 5200+
RAM: Kingston ValueRAM 2GB (2 x 1GB) 240-Pin DDR2 SDRAM
Motherboard: ASUS M2N-SLI Deluxe
Graphics card: Geforce 7600GT
Power supply: Rosewill Stallion Series RD450-2-DB (450 watts)

That's all that's attached for the moment to make troubleshooting easier.

Yes, I'm almost entirely certain that I attached the CPU heatsink correctly... I slowly and carefully followed the instructions that came along with the CPU. I can't take the heat sink off and back on for the moment because I don't have any thermal paste, but I plan on picking some up tomorrow and retrying. However, again, I'm almost near positive that the heatsink and fan are correctly attached.

There were no beeps whatsoever when the case speaker was connected to the motherboard. Just the brief whirring of fans, then silence.

[Cricket]

Do you have another compatible power supply you can swap in to test with? Rosewill power supplies aren't the best quality units out there.

Cricket

[glc]

That Rosewill is made by Solytech - never heard of them.