Fans only

I have a PC that the fans only turn on when I power the unit on. Here is what I have done to it so far:

I have cleaned off the Ram and checked to see of it was a bad stick.

I have taken out the ram and powered on the unit to here the beeps at start up working correctly telling me it is not Mobo.

I have done the same for the Video card.
It appears to boot up when I mess with the video card.

I ran malwarebytes found one virus/back door/ program. I do not believe this to be the problem. I have cleared the system power by pressing the power button at the same time that the power was disconnected from the PC.

I have not check PS but I do not suspect it. I have not replaced any parts on it either.

Any help would be great!

Robert