From what you say, I guess connecting it to the computer doesn't work anymore? (Meaning: The BIOS can't find it anymore.) If it does, try what
Google finds for you. If not, you'll have to ask Professionals (like
DTIDATA or
HardDriveRecovery for example) for help. They will probably be able to recover your files, but they will want money for the job.
By the way, those two companies both sit in the US. If you aren't in the US, I'm sure you'll be able to find a service to do the job in your country.
Greetings,
Nepomuk