How to change my pro duo memory card from "write-only" in windows vista?

When I insert my sony memory stick pro duo, and try to drag and drop files
to it, I get a message that "The disk is write-protected." It also says
"remove the write-protection or use another disk." So how do I go about
removing the write-protection. This is the third card that has given me this
same problem. When I use my cards on my XP partition, everything copies and
pastes like it should. I only have this problem with Vista. I have tried to
go within the folder for my flash card, and tried to change the "read only"
attribute, but it doesn't allow it. I have complete administration
privileges, so that cannot be the problem either. Any help here would be
highly appreciated, considering that I am already at my wits end. Thanks in
advance.