Select the 'affected' drive and run the second option 'Scan and attempt...' the operative word is attempt. Dropping a HDD slaps the heads against the platter and it's worst if it was spinning at the time. You may have lost data permanently, and IMO the HDD needs to be discarded once the data is retrieved - it's damaged and unreliable.
edit: If the scan is finding tons of errors then more than likely head(s) are damaged - STOP - and IF the data is really imporant then stop and send it to a data recovery center. A bad head is going to cause a lot more damage. The recovery places take apart the drive, clean the debris and replace the heads - it ain't cheap!