Hi - my mac mini began to pixelate and freeze after 10 minutes of use 4 months ago. However, once I powered it up a few times after crashing it would eventually stay working. The last time I got it to work I didn't turn it off for a month and if worked flawlessly - which is very strange. I only turned it off because I moved house. However, it now crashes after 10 minutes - the screen becomes pixelated and there is even a pixelated box over the cursor which sometimes stops working completlely. No matter how many times I turn it on or off it won't work for longer than 10 minutes and sometimes the screen goes black when it crashes. Does anyone have any ideas in relation to fixing this problem.