System Won't Post

I am having issues getting my new home built system to post. Right now I have the mobo and psu laying on the desk with an old case speaker hooked up. I have also installed the cpu, heat sink (artic silver 5), RAM, and video card.

When I power it up I hear no audible warnings. The CPU fan turns on as does the fan on the GPU but I get no display. I have tried each stick of RAM separately in each slot. I have removed the GPU. Still no post.

Can anyone see anything wrong with this set up that might keep it from posting? Any advice welcome.


Specs:

GIGABYTE GA-MA790XT-UD4P AM3 DDR3 AMD 790X ATX AMD Motherboard
AMD Phenom II X3 720 2.8GHz 3 x 512KB L2 Cache 6MB L3 Cache Socket AM3 95W Triple-Core Black Processor
XIGMATEK Dark Knight-S1283V 120mm Long Life Bearing CPU Cooler
OCZ Platinum 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Dual Channel Kit Desktop Memory Model OCZ3P16004GK
CORSAIR CMPSU-650TX 650W ATX12V / EPS12V SLI Ready CrossFire Ready 80 PLUS Certified Active PFC Compatible with Core i7 Power Supply
XFX HD-487A-ZHDC Radeon HD 4870 1GB XXX 256-bit GDDR5 PCI Express 2.0 x16 HDCP Ready CrossFire Supported Video Card

Did you try clearing the CMOS. There should be a jumper on your motherboard to do this near the battery (Follow page 33 of you motherboard manual for proper instructions).

Manual found here:
http://america.gigabyte.com.tw/Fil [...] ud4p_e.pdf

If this doesn't help follow all the steps on page 104. Could try reseating the CPU. Is the CPU fan running? Post back if that doesn't help.

Says he has a speaker hooked up. Make sure its plugged into the mobo correctly? Not sure if thsoe can be plugged in backwards, but it wont work if it is. If you have only mobo, cpu and gpu, it should be screaming at you when it doesn't find the ram.



And why the heck am I a newbie again?! Did they reset us?

I actually tried the case speaker both ways because I wasn't sure which side was positive and which was negative. Not a peep. I am going to try flashing the CMOS when I get home per the instructions so graciously provided by dvanholland. I was actually looking into doing that before work this morning but couldn't find it in the hard copy of the manual before I had to hit the road.

Also, I'm going to snag a stick of DDR3 from work to test if I can find one. Actually now that I've looked around everything is still DDR2 so I guess I won't be doing that.

I will post my results tonight.

Thanks jsc I've ran down that list just hadn't had time to find out how to properly reset cmos. Thanks for the heads up on the speaker polarity. Good to know.

Would you suggest this method over shorting the cmos reset jumper?

I read this in my manual which implies that using the jumper has potential to damage the board if done incorrectly. Maybe the battery method has less room for error.

"After clearing the CMOS values and before turning on your computer, be sure to remove the jumper cap from the jumper. Failure to do so may cause damage to the motherboard."

Alright tried both CMOS resetting methods w/o RAM and nothing. Got desperate, ate chinese buffet with wife, came home and took it all down. I removed Dark Knight cleaned the CPU, threw on some more AC and tried it with the factory heat sink. Houston we have post! So I add RAM to the mix and it posts again. I then removed the factory heat sink and fan then clean and reapply AC to Dark Knight. Put it on and it posted again. Next I added the video card to the mix and now I'm sitting here watching it run @ 32 degrees c in the bios.

I think I can chalk this one up to doing a poor job of seating the CPU the first time. Hope I didn't damage it.

Thanks for all your help!