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Stop using the laptop and don't risk overwriting anything on the hard disk.
The ideal way to solve this problem is to use your most recent backup.
As soon as possible 'clone' the hard disk onto another hard disk and make yourself an exact copy. Now you can run some experiment on the cloned hard disk.
Try and use "System Restore" and see whether it restores it to a previously known good setup. Usually this does not affect data but this is not a normal case.
If this does not solve the issue download and run 'RECUVA' -
http://www.piriform.com/recuva/download