I'm sorry to hear that Nado. My headset tends to get caught in my chair's armrest; drives me insane when it gets ripped off my head as I get up.
As far as troubleshooting goes, I will recommend a few things. Please try all of these fixes individually so you can isolate the problem(s).
1) Completely remove the CPU and cooler, clean both surfaces with rubbing alcohol and reapply thermal paste. Check for damaged pins in the socket. Make sure you've got the cooler mounted nice and secure, without over-torqueing, which would damage the motherboard. Get it nice and snug.
2) If your motherboard and CPU support onboard graphics and you have video output through your motherboard, please try connecting your monitor via this port. Another option, if you have one available, is to plug a different GPU into your motherboard and connect your monitor that way, for testing.
3) If all else fails, try a different motherboard that supports all of your current parts; same socket, ram support, etc.
I'm aware these solutions are realistic for all builders. Having extra parts comes in handy.
During this whole process, I would advise you remove your motherboard and make sure no standoffs or screws are bent or have fallen out. You don't want to have a short because of broken bits behind the motherboard or have an insecure mount.