You could try a FORMAT /MBR that used to work on FAT and FAT32 (I don’t know about NTFS). In any case do not work with this PC as the work would re-allocate sectors.
If this does not work, or you don’t want to take a chance, boot from a CD that has an undelete program on it (you must create the CD on another PC). You may be able to see your files starting with a !. Change the ! to another character and they will come back.
If nothing works, get your files back from a backup.