I have a zotac GeForce gtx 960 and just the other day I noticed the fans where not spinning. So I opened up my side panel laid my pc down and turned the pc on to see if I was right. I stood it back up turned it off and turned it back on and the fans stopped spinning again. every time I lay it flat it works fine. I can even set it upright while its on and the fans will keep spinning. Any one have any idea why this is?