Depends on what's damaged. If it's just the enclosure electronics dismantle it and buy a replacement case -- take the drive with you so the retailer can match the interface of the drive.
i would plug it it and go to computer managment /disk managment and see if it is unalocated for some reason? also try diffrent usb port provideing it is external drive i take it. if still no joy buy a new excloser like fihart saidg good luck