A few days ago I got an error when I tried to take a snapshot of my screen. It told me that I couldn't take it because the place I was going to save it to I didn't have permission to save there. I the tried to copy and paste items from one part of the drive to the other . Even just trying to duplicate items on the desktop it would give me a unexpected error. I can't remember the number. I then just went about working on my computer for about 2 more days I didn't shut it down I just let it go into standby. I then got a error message that popped up and it was a force quit window saying that I had maxed out the available memory and to close out of the applications. I closed all the applications open at the time and then I went to the disk utility and checked my hard drive and sure enough I had about 550GB free of a 1TB drive. I then got the error again with the force quit window. I closed disk utility and when I tried to open it again it wasn't able to be found in the spotlight search. I opened a finder window and clicked on the application folder and there was nothing in there . After that the computer just started running very very slow. I click the reset button and then when it went to boot it would just stay at the gray screen with the apple logo and the spinning wheel. I then tried booting in Safe-mode. It would load the bar about a quarter then it would switch to just the spinning pin wheel. After this I went into the single user mode and ran the repair code. It says the the drive was fixed and there was no issues. S I removed the drive and hooked it up to my Mac mini. I removed all my data and ran a the disk repair and it was fine. I was looking up online for a fix and it says to just format and reinstall the OS. When I launch the installer from the USB drive I get to the lion install page. I the click on dick utility and try to format it. It is now giving me a cannot unmount error. I went to terminal and was able to force unmount it but it wouldn't allow me to format it. It would just freeze up. I left it for about 2 hr just invade it was formatting and it was the Same. Is there a fix to this? I really need this fixed by Monday for work.