FAT32 file system usually doesn't cause problems--but NTFS does. If the file system is corrupt, you wont be able to recover it via knoppix. I recommend using Restorer2000 Pro.
In Windows, chances are this drive wont even show up in computer management. And I know if this is the case ERD commander and Windows Live CD's are rendered useless IMO. Try the program listed above (a trial is available here)
http://www.restorer2000.com/You will need to do a search on that drive for all files and partitions and it'll take a few hours depending on the capacity of the HDD. Then you simply check what you want to recover and a destination path for those files.
Let me know if you have any questions or if this just isn't an option.
-Steve
