Copy the DVD Profiler database to your larger hard drive.

For XP, you can find it in C:\Documents and Settings\Username\My Documents\DVD Profiler
For Vista, you can find it in C:\Users\Username\Documents\DVD Profiler

Now launch DVD Profiler and choose:
File --> open database --> browse --> browse to the new location.

After the database opens succesfully, you can remove the old database in the same menu.

Regards