This situation is very common and I personally face this in few occasions.
You have some limited scope but you can try all of these -
1. try system restore
2. if you are using any source control, you can get the previous version
3. use your last backup to restore most latest version backed up (provided you do backups regularly)
4. Try file recovery option -
http://www.piriform.com/recuva[
^]
This is good one and works 80%, depending upon how many times you reboot the system.
Note: if you do system restore, then file recovery option will not be able to get the lost files.
So, make sure while doing system restore.
Lastly, this is a discipline that we all developers should follow to cope up with such situation. Take regular backups always. Don't miss!
Good luck!
Cheers
Sandip