Here is a simple thing you can try, go on windows, copy the files you want to a folder and when you are done, format it. Simple
Judging by you meaning you can't format the memory card becuase you have some files you want to keep.
Sorry if I didn't help
If you mean you can't format it, try this:
http://panasonic.jp/support/global/c...oad/index.html
an sd formatter