I have a segregate hard disk of 320 GB. and all of a sudden the disk crashed is now showing no data. It had data worth 250 GB. Its neither getting formatted and windows is giving error "windows could not format the disk". I have tried recover my files software. I have kept searching data for 5 hrs but with no success.

Please help me how to recover my lost data from such a problem-ed hard disk.

Need help urgently.