PC cant boot after shuted down for a long while.

I have no idea what can cause this.
If i try turning it off and on again it works. But when im leaving it shuted off for ie. Night, next morning all i hear are working fans and hdd. No BIOS beeping.

 

Sounds like the power supply is starting to go bad, try changing it to see what happens..

 

silly me. i didn't mentioned. When I disconnect pc from power, and then connect it again its booting normal.
I Don't have another PSU to check it

 

You need another power supply..

 

I have plugged out and in GPU and HDD and now pc is booting normal. Thats odd

 

Could of had a lose connection..