Why does my pc turn on by itself

[riecep25]

Hello,
why does my pc turn on soon as i plug it up ? n it's not the ramm i tried that already & no beeps either

 

[andy5174]

Did you enable power on by mouse, keyboard or LAN?

 

[riecep25]

i just got it from a friend in when i hook it up as soon as i plugged the power cable it it cutes on and the screen is blck . when that happen to a couple of computers i fexed it was the ramm not seated properly but i'm lost on this on

 

[roonj]

Sounds like the power button could be broken or stuck on, by the way do your parents know what you're doing?

 

[riecep25]

The button isn't stuck i got it from a friend i took the cpu off and cleaned it off & i put thermal paste on it the put it back put in a video card it didn't have on i just got a 500GB hdd n hooked that up mouse n keyboard and as soon as i plugged it in it started running the lights & fans but no picture the ramm was seated right no beeps . everything is plugged in right . i'm lost on this one so i'm not sure if it's a problem with the Mb or what .