3 Tabs open on Safari (Gmail, Facebook, Macrumors). I headed to this website and clicked on the forums tab. The Mac froze. The mouse pointer wouldn't move and I had to press the power button. It may have happened before though I can't recall. Apple Hardware Test is not on it due to Mountain Lion upgrade. Internet based AHT says this machine is not supported. 4GB of memory, 16.47GB hard drive space free (need to offload some Doctor Who seasons). Is is my lack of free hard drive space or should I bring it to Apple to have them look at it (I have Applecare until November 2013).