Fixing this was very hard using many methods given in the net.So i found an easy method.
i)First open your mass storage-Don't delete any files in the steps given below.The files affected will automatically change to older files.
ii)Now create files in your desktop with exact same names of the affected files in the flash drivemass storage.
iii)Check that the files are named exactly as the infected files.
iv)Now copy the files you created,one by one to the mass storage/flash drive.
v)The files copied to the memory card should be empty.
vi)When you copy the files you created from the desktop,the infected files with same name will be moved and the new files will be copied.
That's it.
Please comment if you have any problems.