Signs that your Hard Drive kicks the bucket, taking all your data with it:
- frequent crashes, especially while booting up
- frequent error messages while copying or moving or files
- disappearing files and folders
- long times to access folders and files
- scrambled files or folders names
- unusually loud sounds which you never heard before (clicking, repeated spin-up and spin-down)
In case your harddisk just kicked the bucket, try File Scavenger Data Recovery.