Alright, any tech savvy users want to help me figure out my computer issue?

I recently got a new motherboard and video card and I'm having issues getting them to work. On two separate occasions it has been up and running just fine for days at a time.

But once the system is powered down I can't get it to turn back on. The standby power LED is on so I know there's at least a little juice flowing. I hit the power switch and nothing happens. I got it to start up once by moving the jumpers to clear the CMOS, but that's not working this time. I'll try to give you some specifics to help anyone out who wants to toss me an idea to try.

DFI motherboard NF4 chipset socket 939 with an AMD processor that is supported by the board.

2 1GB sticks of OCZ PC3200 RAM

Gigabyte GeForce 7950GT videocard PCIe

160gb SATA harddrive and and DVD drive

The only thing that looks suspicious is that my powersupply has a 20 pin connector where the motherboard has a 24 pin plug but I was under the impression that didn't make a big difference. The most confusing part is that it was working just fine for several days. oh well, any tips you've got would be much appreciated.

Are you sure your computer isnt going into hibernation? I know mine used to do that and it would never come out of it. If you check your bios there may be an option to change what happens when you shut down the computer - If it goes into hibernation or turns off completly.

So when you have shut down the computer and you have the standby light on what if you pull the plug out and then reattach and turn on, does it work then?

To me though I could be wrong as I have had a near similar experience it was because of the power supply:
Make sure its pushed all the way in - it does help!
Can the power supply actually give enough power for your components?
That 20/24 pin thing sounds like it "Could" be a problem
Have you got other components to switch in and out to test?

Quick google search for your pins:

Check this out first -
http://forums.dvdoctor.net/showthread.php?t=37433

Then check this out and search through the googles -
http://www.google.co.uk/search?hl=en...y+20+pin&meta=

I'm willing to bet that is your problem. DFI boards (which I use) are very fussy about their power supply. They like clean power and a lot of it. What is the make and wattage of your PSU. From the old DFI boards, the preferred PSU's are OCZ, Fortron Source, the newer Corsair and a couple others that elude me at the moment. Cheap PSU's are NOT recommended for DFI boards. Also, a 24 pin mobo WILL need a 24 pin PSU for correct operation. The extra 4 pins are there for a reason.

Thanks Tigur- good links!

The PSU is a 550 watt Antec. The recommendation is 400 watts for my processor. The extra parts I can swap out are my old mobo/graphics card. I think I'll go look at PSU's and see if I can get an adapter or a new PSU and if that doesn't work I'll swap the stuff back out and see if I can get it to work still.

Adapters that switch the 20-pin to 24 pin won't work. The mainboard does the same trick itself (feeds power to the 4 missing pins via the connected ones) and as you can see, with a low grade of success. You will have to upgrade your powersupply to support ATX2.0 (24-pin). Otherwise your system will never be stable. Sorry.

I have put together some computers together (actually, quite a few) and what it sounds like is that it might be a motherboard problem. Especially if clearing the CMOS out before seemed to solve the problem and now it doesn't. The 20 pin power going into 24 pin is fine...should NOT be a problem, as I built 15-20 severs last November with the same get-up and they are still working with no problems. If you can, I would try to exchange the motherboard for a new one if you have swapped out the memory and CPU with the same results...that would be my recommendation. Good Luck.

Wow! You were putting GF7950s into the servers?

The 4 pins that FiremanFred has unconnected happen to feed power to the PCI-express connector where his mighty graphics card is connected.

The servers, running probably on an integrated graphics chip don't need much power, the GF7950 does.

No...that is probably why they work. DUH! hehehe, woooops.

hehe, yeah I guess I hadn't considered just how power hungry this new GPU is. It does look pretty imposing though, as it has a giant heatsink that looks like tentacles spreading out to take over my entire case. At least if the new power supply doesn't fix the problem I can return it.

yep it was the power supply! I just put the old MB and GPU back in and reinstalled Windows and everything is plugging along just fine. (I didn't want to spend more money on upgrading) thanks everyone for helping out

So are you not running your new parts?? Or did you just replace the power supply? Glad you figured it out