I have this same problem with my external hard-drive (every time I go to save a file to it, says the drive folders and files are all write-protected).
I continue to run :
Start > Run "cmd"
type--> list volume
type--> select volume #
type--> attributes disk clear readonly
and it removes the write protection for a short period of time. Unfortunately Windows 7.0 quickly reapplies the "write protection" to the drive, folders & files. I say that Windows 7.0 applies this attribute as I take to other computers and the drive will work fine with XP and prior windows versions.
There has to be a simple way to correct Windows 7.0 from doing this. If anyone knows, please share as I have searched far and wide and have not found the permanent solution (though I have found a pletora of others with the SAME problem).