I don't believe the inability to start is the fault of the cooler (which is a cooler master Hyper N520)
I had my desktop computer (home built) turned off for a just less than five days since I was out of town. The PSU was still plugged in and turned on during that time, but the computer was shutdown.
I returned home (with the new CPU cooler I got for christmas) and the next day (today) decided to replace the current cooler with the new one. The new one required me to remove the thing that attaches to cooler to the motherboard, and replace it with one designed for this cooler (which makes me wish I had asked for the Hyper 212). This obviously required me to remove the motherboard from the case in order to attach it. Stupid, impatient me, decided that instead of going out and getting an anti-static wristband, I could just ground myself to another piece of metal (so I haven't ruled out static damage.), I used either a music stand or the computer case while I removed the motherboard and attached the new cooler (depending on which one was easier to reach) and before you ask, yes I did apply thermal paste. I proceeded to put in back in place (screws and all). While I had it open I dusted the inside. I also removed the GPU and removed its cover so I could get the dust out of it. I put my desktop back together as it was before, closed it up, and attempted to turn it on. I pressed the button and that's when I heard a somewhat loud POP. When I turned it on, everything was fine for a few moments before the pop. After the pop everything was running fine except nothing was appearing on either of my screens. The fans were running, lights were on, but it just wasn't doing anything. I could still perform a hard shutdown by holding down the power button. After I shut it down, I opened it up and I could smell something burning (still haven't determined what it was though, or even where it came from). Just to test I tried turning it on. For less than a second it held on power (LEDs were on, fans were turning) then it immediately turned off on its own. The power button didn't work again until I unplugged it, waited for the LED indicator on my motherboard (it indicates if it's receiving power) to shut off and plugged it back in. After that it does the same thing. Everything I've read points to a PSU failure, but I don't think I'm that lucky. I did the paperclip test on the PSU and it passed (the fan ran on the PSU). I don't have a PSU tester currently.
At this point I just need to know where the problem is (because I can't really fix it otherwise, obviously). I can't find any visible damage (though I haven't opened up the PSU, or taken off any of the heatsinks on the motherboard other than the one covering the CPU and as far as I can tell the cpu is fine)
I don't have another powersupply or computer at all to test anything on (using a laptop currently).
I don't have enough money to waste on guesses. Hell, I don't really have enough money to waste replacing the motherboard (if that's the problem as I suspect) because I would also have to buy a replacement key for windows (since I used an MSDN license to obtain my current install and I lost it and can't obtain another one.)
Motherboard: Asus M4A79XTD EVO
CPU: AMD Phenom II x4 955 Black Edition
GPU: EVGA NVidia GeForce 9800 GT 512MB
New Cooler: Cooler Master Hyper N520
PSU: OCZ GXS 600
Case: Cooler Master Centurion 534+
Other info: I had 2 hard drives plugged into the S/ATA ports and one disc drive plugged into the IDE port (the HDDs were both normal hard drives) and I had a card reader plugged into an internal USB port. I also had 3 case fans plugged in.
as for this post, I wasn't exactly sure where to stick it, since I'm not entirely sure where the problem is
I removed the graphics card and turned it on with everything else plugged in (omitting a couple of non-essential fans, the case is open) and it turned on and stayed on (not immediately turn off). It then proceeded to beep at me (dash dot dot dot). It stayed on until I shut it off.
okay, I got it to work (sort of) by moving the graphics card to the other pci-e x16 port. It came up and booted, I was able to get to the CMOS setup (which had reset itself to default). I was pressed for time, I had to leave the house shortly after. I came back and it's like a little gremlin rewired everything while I was away. I started plugging more things back in (everything really, hoping for a full run, the run before was bare essentials to get things running) and I turned it on, and well... the power button isn't quite a power button anymore. It's a LOW/HIGH button now. If I have the PSU power on, all the fans turn on (and for some reason it seems to have trouble supplying all the power, it wouldn't work at all for a little while, but everytime I plugged the PSU in, my lights would dim and I could hear the fans go and then instantly it turned off, I got it to stop shutting off instantly, though I don't know how). I can press the power button to turn the fan speeds from high to low. but that's all it does. The reset button changes it from low to high however long you have it pressed down. I don't know what the hell is going on. There is absolutely no video output, no boot up beeps, as far as I can tell no POST. All it can seem to do is power on small fans. The CHA_FAN2 power port also doesn't seem to work at all.
also, one thing I forgot to mention. I think the original PCI-e x16 port is the thing that got fried. It doesn't work and it looks like there's dust in the port for it but I don't think it's actually dust anymore.
Loud pop and burning smell, likely the power supply. I'd quit using it before you cause more damage to your components. You're best off just replacing the power supply and hoping it hasn't damaged any of your other components yet.
disconnect all extra fans.then power on.remove all usb devices.
I've already done that with mixed results, and I'm honestly, right now, trying to mitigate any extra damage I've caused by doing that. I'm already getting weird power issues. It's been suggested that it's my power supply, and I don't want to power it one with the motherboard or anything else attached until I know for sure. I don't have enough money to replace the PSU and anything else. I just barely have enough for a decent PSU at this point. I'm going to see if I can get my hands on a PSU tester this morning.