All the items (both files and folders) inside my pen drive had been renamed to some characters like :]h.¡>?.A++ and when I try to open any folder Windows gives this message.

The filename,directory name, or volume label syntax is incorrect

I was told that it is a problem of the pen drive, not a virus. They say if I format the pendrive then I will be able to use it again normally. But I'm not sure. And I need those files.

Does anybody knows a solution?