I am experiencing issues similar to the previous post. I have read through those posts and have had simliar issues and tried simliar things.

Basically, I built my first computer in October (a gaming rig, i can post specs later if needed). It ocassionally shutdown (maybe 5 times total) when I was playing BF3 or Skyrim (but otherwise worked just fine), so I decided to get an aftermarket heatsink to cool the computer down.

I took everything apart, installed the new heatsink, and plugged everything back in. I hit the power button and then it came on (LED lights and fans) and then immediately turned off. When I hit the power button again nothing happened. I had to unplug and replug the PSU to get the computer to turn on for a second and turn off.

I have read that some CPU have a heat protection, if the CPU fan doesnt seal well with the CPU, it will turn off the computer. To test this, I started the computer on its side (the fan vertically on top of the CPU), and got the same result...

Long story short, I realized the new heat sink braces touches the case, so that is not good. So I switched back to the original heat sink fan (ie my original working setup), but now it does the same thing. It turns on for a second and then off.


So my question is:

When I accidentally grounded the mobo (assuming I did, right?) with the larger cooling bracket, did I damage the mobo?

I dont think it is the power supply failed because the fans turn on and it seems like a crazy coincidence that the power supply would fail the same time I switched the CPU fan (unless I overamped the PSU with the larger fan?)

I have been messing around with this for a week and any help would be appreciated!

Thanks!

not advisable grounding the board but ive done it with no long term effects, i know your going to think thisd is a daft question, did you use thermal paste when fitting the new and refitting the old heat sink fan, and theres a very good chance you didnt short out the board, ever if ithe fitting ouched the case

i used rubbing alcohol to wipe the old thermal paste off, used the thermal paste included in the heat sink kit (about a grain of rice), and then attached the new heat sink...

I would think its related to that somehow. I only changed the fan and now it wont turn on.....

sounds like youve done it right, im wondering if theres some kind of cool and quiet type of program activated in bios, try popping the bios battery out for ten seconds and replace it, assuming the heat sink is fitted flat against cpu and fan is running, its going to be an uprated heatsink most likely so if fans running it should be better than what was on it before, also if you can look in bios and see if theres any temps listed, see if it will boot in safe mode, and make sure theres nothing connected loike printers, external hard drives, flash memory sticks etc, just keep k/b, mouse and monitor, if it starts in safe mode download core temp to make sure overheating isnt problem

I would try the old "disconnect everything & reconnect one at a time" routine.
Leave CPU, heatsink & fan installed (make sure the CPU is in it's holes correctly), use just 1 stick of RAM making sure its inserted good. Leave the power connections to the mainboard and fans connected. Disconnect the hard drive(s) and the DVD/CD drive. Make sure your video card is inserted securely. Now, see if it will pass POST. Of course it will not boot all the way, but you should get things on the screen eventually advising that there is no boot disk. If it at least does this, shutdown and insert anthoer RAM stick, reboot. If its a no go then its bad RAM...if it boots past POST then shutdown and reconnect the hard drive, reboot. You keep reconnecting things until it starts acting goofy again.
If it will not get past POST from the first step then you have either a power supply issue or a motherboard issue. Get a cheap power supply tester and test the PSU. If it checks out okay then you've narrowed it down to the mainboard.

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I would think its related to that somehow. I only changed the fan and now it wont turn on.....

I believe you said you tried the old fan again with the same results...I don't think it's the fan. I could be wrong, though.

hmm so i switched BIOS battery, same result -on and then off immediately

i unplugged everything. then i plugged in cpu, heatsink, 1 stick of ram. i set the mobo on cardboard (free from case and accidental grounding)....got same results....

so its gotta be the mobo, cpu, or PSU? i am getting a new PSU tomorrow so hopefully that does it...otherwise, i may have go back to my laptop + ps2

you can pick up psu testers on ebay from £2(at that price quality isnt going to be great or number of features), or swap out a known good supply, try the different sticks of ram one at a time in different slots, if it comes down to m/b or cpu (unless the cpu has been removed and theres a chance pins could be bent) m/b is most likely the problem.

I would see if I could Borrow a power supply first,if you don"t have tester