motherboard? problems

[jackall]

so a few days ago i opened my PC to clean it up really good and so i did
after i reassembled it and turned it on i noticed the green LED (power on) wasnt working at all although it isnt dead and the monitor doesnt turn on
what do you think is wrong with it?
i connected every wire from the front panel as the manual shows, the RAM is well fixed, so is the CPU and video card

 

[UndeadDragon]

Are you actually getting any output from the computer? Does it make a beep when you turn it on?

 

[jackall]

no, only HDD is making any sound that its alive whatsoever

 

[UndeadDragon]

I would check the power connections on the motherboard. It may be that not enough power is getting through.

 

[jackall]

ook, ill try that aswell, had it before because of some unknown problem... the original PSU was 350W but after like 2 years it got damaged i suppose so i had to go get a new one of 400W and it worked

 

[UndeadDragon]

It might not be that the PSU is broken, it could just be as simple as not all the power connections are plugged into the motherboard.

 

[jackall]

only the 20(?) pin one needs to be, no 4/8-pin, no video card power cable needed

 

[FireCat]

no video card power cable needed

No? But you need to plug the monitor's video cable directly to the video card.
It does sound you didn't lol

 

[jackall]

unfortunately i did...