Computer doesn't start up

[mohamedayoubmanai2006]

Hello, today i've tried changing the ram of my computer. after that, i've started up the computer, the power button used to make blue light, but it hasn't done anything, and the cpu fan, it keeps stopping and working again n every 5 seconds (feels like the computer keeps restarting). i've looked at the inside of my pc again, and i found that there are some cables MAYBE got unplugged out of the mothercard... i'll send some pictures later but can anyone help me with these cables? or just tell me what's wrong? (btw i've tried putting back the old rams but it didn't work: so it's the mothercard for sure).

 

[snadol]

If you can send pictures of the cables, that would help a lot. That's probably the issue.