When a drive goes bad it is usually a catastrophic failure and not all data is recoverable from the drive, if at all. That is why backups are important.

In case a data recovery is needed there are a few options


Software

You can attempt to recover your data with software from a dying hard drive if there is not any mechanical problems with the drive. Please see this knowledge base article


Data Recovery Service

The drive has to be shipped to these services which for a fee (sometimes quite large), will attempt to recover your data.