The horror I backed-up all of my critical documents to a USB memory device when I was running 2000 after upgrading my PC to XP-Pro Now when I try to access the device I get a message saying this "disk needs formating"

I had a similar problem with a corrupted USB drive. I used
http://www.z-a-recovery.com/
and I was able to recover everything. The free download is full featured but you can only do so many files at a time... but you can always just exit/restart the program.

Thank-you I will give it a try.

Another good utility is GetDataBack (for FAT or NTFS as appropriate) from www.runtime.org. After scanning the system it can recover files one at a time for free by opening the files with an installed program that can use the files. Otherwise you must pay to recover them by simple copying across.