Data Recovery comes in 2 basic formats ..Physical and software based.
Backups should be made prior to any data recovery attempts.
Simplistic options in a stand alone environment are wide, ranging from operating system recovery programs to third party recovery programs.
We recommend if your data is crucial that a technician be called. All systems are as a last resort based on recovering data from backups...so keep backups up to date. Part of the backup system should be a set of disks called boot recovery disks. This is a set of disks which is based on the operating systems start for your system , and is created for just these type of scenarios.
Tape drives/hard disks /edisks/xdisk/cd/dvd/etc., are all backups that can be used & should be utilised for your companies safety.
Remember, keep 1 disk off site (at home) so that if the building is destroyed, it will still be possible to recover the majority of your data.