From there i can get to the command prompt.
At the command prompt type
Diskpart and hit enter
then type
list disk and hit enter
is the disk you are having trouble with, listed there?
IF so and depending on what your intentions are and how much you care about what might be on the disk you may not want to proceed with the following
After using list disk, if the disk is included in the list it will have an associated number as in Disk 0 or Disk 1, etc.
Type
select disk # (where # is the associated number of the your problem disk)
WARNING: The following will wipe the contents of all partitions on the disk that you chose in the step above
Type
clean and hit enter
All gone, so..... Again, be careful and know your target disk and that the consequence will be everything is gone..... No OS..... no data..... no anything.
IF your intention toward the disk is anything other than wiping it out and performing a clean custom install of the OS, then ignore all of the above.
You should probably attempt to attach the problem drive to another working system and see if you can manage to backup the contents of the problem disk, or......
Go to the disk manufacturer's website and obtain their proprietary diagnostic utility to perform tests on the drive and see if it needs to be RMA'd
