If the hard drive was corrupted in the bios or OS, you still can recover the data. It will cost you some money, but you can go to computer store and ask them to assess the damage in the disk and the possibility of recovering the data. It happened to me more than once. I learned my lesson to have a regular (daily) backup (external hard drive) system now and 3 computers with all my data (work and personal data) synchronized.
M