I have recently switched the CPU cooler on my mainboard. After i was done my monitor wouldn't get a signal from my GPU anymore.
I tried using different Graphics cards and they would not work neither. However i was able to get them to work at another computer so the problem must be within the motherboard itself.
I am currently using onboard graphics which work perfectly. Í tried everything to make it usable again (using VGA/HDMI/DVI cables, checking BIOS settings, checking the device manager in which my card wouldn't show up anyways, even resetting the CMOS on my mainboard) but i can't seem to get it to work.
I made sure the card was inserted properly everytime i broke off the latch one time when i pulled too hard ( don't know if that is relevant) and there is no damage visible from the outside.
Whenever i insert a graphics card into the slot the fan is spinning, but when i plug in a cable my monitor just goes into power saving mode after being dark for a few seconds. My system is the following:
CPU: I5 2500
RAM:8GB 1333 Team Group
GPU: ATI HD 6870
IMO find some thin plastic washers and insert as above. Unless you have an i5-2500K + P67/Z68 there's really no point in not using the stock HSF; neither your MOBO or CPU can be overclocked...try the stock HSF. If the GPU works with the stock HSF then you have your answer.
Remember, you MUST replace the TIM (Thermal Paste). It can never be reused so clean-off thoroughly with a lint free towel or paper Coffee filter and with Isopropyl alcohol, then allow to dry 5~10 minutes. Good TIM like Arctic Cooling MX-4 is the best choice - http://www.newegg.com/Product/Product.aspx?Item=N82E168... it's non-conductive and is one of the best TIM's out there. I use it
IF you used too much TIM and it squeezed into the CPU socket then that's a real problem especially with conductive paste.