You meant that the drive asked you to format it before you can use it? If so, here the solution.
Firstly,recover your files off the drive with data recovery software.Then you can format it get it fixed.For data recovery software,I have a professional one called Tenorshare Data Recovery on my computer that can recover data after deeply scanning your hard drive to look for lost data due to drive crash,system sabotage, virus corrupted partitions,etc.You can download it and scan your hard drive for free to preview whether your data can be recovered. Get it from
http://www.any-data-recovery.com/product/datarecoveryprofessional.htm
By the way,if you can't format it as normal,format it with low level format tool like Any Drive Formatter...