Help!!! I have a 2010 Mac mini that I use for a home theater computer. I run snow leopard and recently updated to El Capitan. That's were things went crazy, it would freeze and video output wasn't right the only way I could turn it off by holding the power button. I used time machine and went back to snow leopard and alls well. I thought maybe I should do a clean install of snow leopard and start fresh and try again. I Installed Yosemite this time, I didn't load any movies or songs and had the same thing happen? Back to snow leopard and alls well. The only thing I see in log is this. Nvda (OpenGL) exception exception type=and=Graphics engine error (gr error5)? Only happens with Yosemite or El Capitan not in snow leopard? Any help is appreciated in advance. 2010 Mac mini 2.4ghz 8gb ram 320gb hard drive.