last night my iMac semi froze on me. it's weird because I can still use my BT keyboard and mouse but when i try to click on anything it doesn't work. now the dashboard and expose functions work as well as do keyboard shortcuts but when i try to click on any icon nothing responds. it's like everything on the computer seems to be working except for clicking, has this happened to anyone else ? any help would be great, i'm posting this on my iphone. thanks !