Hi- I have a Mid 2012 15" MBP. It keeps freezing mid-task. I can still move the mouse but not click on anything. The only solution is to power down the computer using the power button. This didn't seem to happen before upgrading to Yosemite. Anyone else with this issue? This happens multiple times a day. I tend to have multiple browser windows open, with tabs in each and a few word docs and spreadsheets open. But I've always used it heavy like this and never a problem. When I restart it comes back on with a message about a "graphics problem had occurred" or something similar. I always chose to report. Something serious going on here? The freezups are really annoying.