Remove the virus > open with file explorer (folder view) > copy all ur data from flash > format flash > replace data - keep anti virus scanner active while copying the stuff or else will invect whole machine! I get this with flash drives about 1nc a week. If u dont format it, it will only open in autorun (when u plug it in) or via the folders tab in XP.
Can however be wrong and it might not be what i think it is and you dont have to format it. Nevertheless ALWAYS back up ur data!