RAW/NTFS issue and Recuva - "path not valid"

Hello,

I have partitioned my external hard drive. One partition works fine, one isn't accessible any longer - I have had it for over two years and it has always worked until now.

Disk management does identify the inaccessible partition and shows that the format is in RAW. I am using Windows 7 and it is prompting me to format it. I tried changing the letter assigned to the drive but that didnt make any difference. I have tried various things and received numerous error messages such as "path does not exist" or "cyclic error" etc. Windows wants me to format the disk before using it.

I have downloaded Recuva but when I select the inaccessible partition it says "path does not exist".

Disk Management shows the drive as "healthy" and I have run various antivirus checks and everything seems fine. Windows Recovery did do its job - took over 2 hours - and I selected "attempt to find and fix bad sectors" - it completed its job but hasn't made any difference.

Please can you help me? I need to a) make a backup before attempting a recovery and have no idea how to do that given I cant access the drive and b) convert the drive back into NTFS so that Windows 7 can access it.

Thanks in advance