No display pc, possible heatsink not attached correctly?

[AdriaanC]

Is it possible my pc wont boot if the heatsink is not attached correctly?
It boots in 2 times, everything is spinning but there is no display.
I also don't hear any beeps.
I unplugging everything but no beeps.
I really hope its not a motherboard issue.
Motherboard worked with these componentents but recently reapplied therminal paste and put it in a new case, everything used to work i don't know what i did wrong.
Would appreciate any help.

 

[ChumP]

If you've only change the thermal paste than you can reapply using vertical line method or grain of rice method and then reattach correctly the CPU cooler.

 

[George Phillips]

If the heatsink is not attached correctly, the PC would still boot but later would overheat. I'd remove the components I had reassembled and clean them again before putting them back to test it again.