Don't know if my socket is broken

[Piripuz]

Hello.
I disassembled a pc, I assembled everything back in and after this it worked. But the day after, when I turned it off and tried to turn it back on, it wouldn't work. All the fans started spinning, but the screen was black, just as when you turn a pc on without the cpu. It wasn't a graphic card problem, because I tried with another graphic card and it worked in the exact same way. The cpu is OK too, and also the ram is working. The socket seems really OK, but I cannot imagine where the problem can be.
Anyone had the same problem? Where can the problem be?
Thank you

 

[okcnaline]

Is the socket broken? Just take the CPU out and look if the socket's gone.

 

[Piripuz]

Is the socket broken? Just take the CPU out and look if the socket's gone.

No, it seems perfect. All the pins are perfect, just like a new one.
Thank you for your super fast answer

 

[okcnaline]

Try taking out and putting in the CMOS battery.

 

[Piripuz]

Try taking out and putting in the CMOS battery.

I did it, but it's still not working