Hi Clembo!
A great work around for this is to add a partition or secondary HD to the computer so you can place all the files you want to keep on it, and you can still format "C:" drive. The partition will most likely have the letter "D:" drive, and will not be formatted, no matter if you switch between 32bit and 64bit.
This way you no longer have the need to burn backups when you format, and is valued when your OS becomes currupt or any serious error will not allow you to gain access to "C:" drive.