How can I recover data from an external hard drive?

I got a friend calling me because he made a program for this Doctor using MS Access 2003, the program was running on a external hard drive since september last year. Suddenly all the data was missing, he checked and the software created was intact and working perfectly. The one thing he found strange was the date. The hard drive said that the data was last updated at September 2007, which is weird because this data was constantly changing until last week.

If someone out there knows a way of getting that data back, please leave a respond.

Any help will be much appreciated!!!

PD: The backup is no where to be found.