Question Black screen problem

[trabelsiadem5]

I tried to clean my computer and to change its thermal paste however when i finished and tried to turn it on, the screen won't show a thing it just stays black
PS : i made sure of all the compoments they are well installed .

need help, what do i do ?

 

[alexoiu]

An internal speaker would help in troubleshooting, if no debug LEDs on board.

 

[computerjoe314]

Here is a helpful list of things to try

"No POST", "system won't boot", and "no video output" troubleshooting checklist

"No POST", "system won't boot", and "no video output" troubleshooting checklist This checklist is a compilation of troubleshooting ideas from many forum members. It's very important to actually perform every step in the checklist if you want to effectively troubleshoot your problem. 1.Did you...

forums.tomshardware.com

 

[shiriken]

Try clearing the cmos on the mobo