Koray,

What a crappy feeling. If the .wbk file doesn't work, you might try
some undelete tools to mine for the data. Here are some freeware
undelete tools:

http://free-backup.info/data-recovery-software.htm

Ultimately, you should have a backup plan that at least backs up your
critical files once per day to a second disk drive (not a second
partition on the same drive!). There are all kinds of affordable remote
backup plans that are good for this. Here are a collection of freeware
backup tools to at least get you started:

http://free-backup.info/backup-software.htm

Good luck!