I've just built a system from parts, and for the first time ever (this is about my 6th build) the system won't POST.
Fans spin and there is activity on the CD-ROM (lights anyway), but there is no signal out of the HDMI or VGA on the motherboard. Bad news.
I'm suspicious of the motherboard because I get no power LED or HDD LED (if I reverse polarity on the power LED I get a dim glow; definitely not right for this model case, which I have used before---though this particular case is new).
I'm also suspicious of the CPU because the heat sink doesn't get even the least bit warm.
I'm positive I put a blob of Arctic Silver 5 on the CPU heat spreader before mounting the cooler.
I'm seeking advice about how to proceed.
The components I used are as follows:
Antec Solo Black/Silver Steel ATX Mid Tower Computer Case
SeaSonic S12 II SS-500GB ATX12V / EPS12V 500W Power Supply
ASUS M3A-H/HDMI AM2+/AM2 AMD 780G HDMI ATX AMD Motherboard
AMD Phenom 9850 BLACK EDITION 2.5GHz Socket AM2+ 125W Quad-Core Processor Model HD985ZXAGHBOX
Kingston HyperX 4GB (4 x 1GB) 240-Pin DDR2 SDRAM DDR2 1066 (PC2 8500) Quad Kit Desktop Memory Model KHX8500D2K4/4G
Seagate Barracuda ES ST3250620NS 250GB 7200 RPM SATA 3.0Gb/s Hard Drive
SAMSUNG 20X DVD±R DVD Burner with LightScribe Black PATA Model SH-S202N
Well, right out of the gate, I'd suggest a few things:
Make sure the CMOS jumper is correctly set to "normal" mode. Probably wouldn't boot properly in "clear" mode.
Sounds like you probably have some spare parts laying around, try to use a discrete video card; you may be able to at least verify the function, or lack thereof, of your onboard video, at the very least.
Related to above, the BIOS may be trying to send video signal to the PCI-E slot first. This was more of a problem on old AGP boards, but if the stand-alone card works, there may be a setting for you in the BIOS to change the default boot video.
Perhaps check to make sure all your motherboard power is connected properly; it may not be seated all the way down?
Unplug all the other devices (DVD, HDD, sound card, if applicable.) There may be a conflict there.
Forgive me if some of that stuff is rather basic, not to insult your skills, just that those things may be easy to overlook sometimes.
If you're talking about the CPU power connector, YES it's absolutely necessary - it provides power to the CPU. The computer doesn't have a chance of booting with no power to the CPU. The motherboard owners manual will give you more information. Here's a checklist to go through for further troubleshooting: