Annie had a video file folder on her computer that disappeared. The folder, files — everything. Leo suspects that a disk error occurred and when it was cleaned up, it was removed. More likely, the folder entry in the file allocation table was removed. Chances are, the data is still on her hard drive, they just can't be seen by the OS. It's like losing a card in a library card catalog.
Leo recommends Piroform Recuva. It can recover the data by scanning the hard drive for her data and then rebuild the file allocation table to include it. It also means that she may have some bad sectors on her hard drive and it may be time to replace it before it crashes completely.