AHH! Help Me please. I am right now at a library computer, because my computer has had a problem. Last night, I set to "Defragmenting" my D drive. (Not my C drive, where windows is installed!) This morning, I went up to the computer, and when I moved the mouse, the screen would not come back on (it goes into sleep mode). SO I restarted, and got the message "Operating System Not Found"!! What has happened and what can I do about it Please help, because I have gigabytes of data on there that I just can't lose, but I would rather not have to spend hundreds of dollars to save my HD! Thanks!