Aspire 7552g-6061 Fails to POST unless hot.

A friend gave me his broken Acer Aspire 7552g-6061 as payment to help him build a new pc. The only problem with it is it fails to post on a cold start no matter the conditions. No HDD Light or Wifi light. However, after taking it apart to clean it, testing the ram, and putting it back together. I found I could get it to post 100% of the time If I stuck a small screwdriver INTO the fan to stop it from spinning, turning it on and letting the metal plate under the keyboard get hot to the touch, then unpluging it, re plugging it, unblock the fan, then turn it on. The fan will instantly kick on at full speed, the HDD light flashes, then stays on and the screen lights up and it boots into windows just fine. The laptop does not over heat or throttle down under heavy load.

Sorry if thats hard to read I'm kinda in a rush.

TL;DR I think the fan not be able to spin at the required RPM for it to POST. But thats only a theory. Can this happen?

 

I don't think it has anything to do with a fan- more like a mobo failing.
I've had a situation like that where one of the chips that was glued to the mobo needed to be heated up with a hair dryer which would make the glue soft and chip would sink in and work again (and yes I really mean glue)