My PC don't want to switch on?

I cleaned up my pc this morning, so i remove my motherboard and other component including the RAM, GPU, and other possible thing... basically all the removable component...

I do reapply my thermal heat compound on the cpu, n before reapplying i removed the old thermal heat compound using metal knife cause i think it will be nicer to have only the new thermal heat compound that i just bought.

So i open up the PSU too to clean all the dust inside it... after that... i installed all back to the place n try to switch on my PC... but then... no action made... not even a beep sound...

i thought my PSU broken... so i check the PSU by using a wire as a jumper on the ATX head... n the fan n the power on each end cable are just fine... 12V 5V or 6.8V... no problem with the PSU...

so now i guess it is the CPU that faulty... cause of the knife i used to removed the thermal heat compound... so what i want to ask...

How can i make sure that the CPU is broken... n how can i check that other component are OK...

I don't done any electrostatic precaution if it will help to solve my problem...

Right now i don't have any PC to work on... i wrote this thread from my friend PC which live not far from my house.... so to anyone who know what is the real problem... or any way to trouble shoot my problem... please do advice me...

thanks a lot to anyone who can help or willing to help....

you pluged in the 4 pin plug from the PSU

find someone with same socket motherboard, put ur cpu into his pc to check if its blown, does the light on the motherboard turn on when the power is plugged in if not check the the power plugs to the motherboard, also check u plugged the right 4 pin into the motherboard,there are 2 one that goes with that 20 pin plug and the other for the cpu, they both 4 pin but are different

as far as i know if the cpu was faulty the mobo will start up, the screen will just black

never use a knife in a pc man lol

i doubt removing the paste with a knife would have broken it hey, unless you stabbed it a few times or something like that

sounds like your mobo is not getting any power

also you never open your psu man never ever open it, try a different psu

toilet paper workx way better at removing paste lol