Today I was installing a new heat sink in my wife's computer, and I think I may have potentially damaged the motherboard. I've tried a few things to figure this out, but I'm just not sure.
First, here is the build, used mainly for gaming and internet:
ASUS M4N75TD AM3
EVGA 01G-P3-1373-TR GeForce GTX 460 (Fermi) Superclocked
AMD Phenom II X4 965 Black Edition Deneb 3.4GHz
G.SKILL 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3
ARCTIC Freezer 7 Pro
Antec TruePower 2.0 480W 24/20pin Power Supply
There is also a CD/DVD-RW drive, as well as a media card reader.
The overall build is about 2 years old, though the power supply is from a previous build and is probably closer to 5 years old. I used it because I didn't have the money at the time to buy a new one, and it seemed to have just enough power for the build. I don't think this was the cause of the problem.
This isn't the first time I've built a computer or installed a heat sink, though I only do this once every few years, and I only do it as a hobby. However, I know the steps to take be careful, and I always use the manual when doing such things (this stuff is too expensive not to).
After I got everything installed, I plugged in a power cord to make sure it all worked. The DVD drive light came on, the hard drive light blinked, my motherboard's leds were on, and all of the fans were working. Assuming I succeeded, I went to put it back at her desk and the monitor would not get a signal from the computer. I tried the second monitor port, but got nothing. Thinking I damaged the GPU, I installed an older one, but got the same result. This time, I tried using the mouse and keyboard, and noticed that they weren't getting any power.
I moved the computer back to my work table, plugged it back in, and turned it on. I tried a USB flash drive in each of the usb ports front and back, and it did not work in any of them. I took another more powerful power supply that I use in my own computer, plugged in the bare minimum, and tried again, but still got nothing from the USB ports.
As far as I can tell, I didn't miss anything when wiring up the power supply.
Does anyone here have any other troubleshooting suggestions? I am glad that it doesn't appear as though I broke the GPU, but I am rather upset with myself that I might have broken the motherboard.
I would take it outside the case and test again (just to make sure it isn't a short related issue). And you can better control the components installation. Can you connect a case speaker to the motherboard?
First try to reset the cmos with the jumper on the board.
Did you have to remove the board to swap the heatsink? Do you have the PC speaker connected(any beeps)?
EDIT beat to this part \EDIT
If that does not help, remove the board from the case and just leave the cpu, 1 stick of memory and the video card(if it does not have onboard.). So this means not drives or anything just the board on its anti static bag or similar and powered on the table. While the power is off, pull the battery and try another cmos reset.
Now try to get it to post(start up info on the screen.).
With the board out look for any signs of damage as well
Post back if you have any luck.
Removing and reinstalling the memory never hurts in case you bumped it loose as well. Also I sure hope you put new thermal paste on the cpu with the new heatsink.