Cleaned up the PC, now i just have a black screen at boot

[Decimated]

My PC was starting to be sluggy in games where it shouldn't so i decided to clean it. First, i got the graphics card out and cleaned it with compressed air ( its a zotac gtx960, and i also unscrewed it's metal case before cleaning), then i removed the CPU cooler ( it's a stock intel i3 cooler) but i did not replace or touch the thermal paste ( my pc is ~2 years old) and then i just cleaned it all with compressed air. Great, i put everything back together and power up. The fans are working, except the GPU ones, there are no lights (from the keyboard/mouse/fan), no beeps, no POST and my PC shut itself down after a few seconds. Then it powered up again by itself and shut down again. And again. And again. I removed it from the power plug, reseated the GPU and removed a RAM slot that was kinda loose. Now when i power up, the gpu fans spin 1second and stop, there's still no lights, beeps, POST.
What do you guys think it's the cause? Thanks a lot !

 

[captaincharisma]

if the computer shuts down after several seconds it sounds like the cooler is not installed correctly and the CPU is overheating.

 

[Decimated]

It did that before i reseated the GPU and got one of the RAM sticks out. Now it just stays like that with blackscreen until i shut it down manually.

 

[tsnor]

I stopped reading at "...then i removed the CPU cooler ( it's a stock intel i3 cooler) but i did not replace or touch the thermal paste.."

If you removed the CPU cooler then you MUST clean off the old paste and apply new to reinstall the cooler. Plenty of videos on youtube to show you how to do this. Your CPU is cooking right now if you power up the pc after putting the heatsink back in place with the old thermal paste.

 

[Decimated]

The thing is, i didn't have any thermal paste and i live at the countryside, there's no such thing here. I will purchase it online and hopefully it's gonna fix my problems. Thanks a lot!

 

[tsnor]

The thing is, i didn't have any thermal paste and i live at the countryside, there's no such thing here. I will purchase it online and hopefully it's gonna fix my problems. Thanks a lot!

Good Luck. Glad you are getting thermal paste. Do watch a few videos on youtube that show you how to apply paste... it's not hard but you don't want to be confused on how much to use and where to put it.