I'm running 64-bit Windows 7. Windows Explorer will suddenly mark folders as read-only--with the blue fill-in, indicating not everything in the folder is read-only, but something is--yet none of the files in the folder are read-only. If I clear the read-only check box in the Properties window, and select the radio button to apply the change to all files and folders within the folder, the change appears to work, but as soon as I check the properties for the folder again, the blue fill-in for the check box is back.

I can no longer copy these folders to a DVD to back them up because then the DVD is treated as read-only.

What's going on, and more important, how do I fix this?