[SOLVED] Case fans starts and stops with power button giving light but PC won't boot

[HyperChronus]

Greetings,
last 7 days have been an agony for me so if someone could help it would be awesome.
I opened up my PC to clean it and to clean off the residue thermal paste on the mobo. I cleaned it, added new paste and tried to boot. PC started normally for few seconds, got a "beep", fans spinning and then 3-4 seconds later it restarted. It did that 3 times and then I shut it down (with button) so I can inspect the issue. When I removed the CPU to see if everything is good I saw that I bent few pins on the left side. I straighten them up, put the CPU back and tried to boot.
This time fans only started to spin for half a second and then they stop, CPU and GPU fan is not running but the LED that's attached to the power button is turned on.

I wen't to a local repair shop and he said that it can be either mobo or the CPU issue but because he doesn't have a motherboard that supports my CPU (literally 0 people in my city does) he said that I should test the CPU before trying to get a replacement board.
I tested the CPU in the local repair shop and they said that It was working. Yesterday I finally managed to find a board for this PC in working condition. I once again took it to the same repair shop that tested the PC in the first place and when he tried the CPU on new board he said that it had the same issues as before (he tried multiple PSU). I really don't know what to think now, which part is most likely to be broken.

Thanks in advance

Specs:
I7-6700K
Gigabyte h110-d3u (current mobo), gigabyte h110m-ds2 (donor mobo)
550W thermaltake PS
1060 6GB
16GB (2x8GB) Patriot 2133Mhz

 

[Fix_that_Glitch]

Do you have a magnifying glass so you can inspect your pins very closely for any bent pins or debris/thermal paste. Same thing for the cpu slot. If you don't find anything, install cpu and remove gpu, and connect monitor to the motherboard to see if motherboard will boot up.