What do you want to do with the partition?
Does it have data on it you want to keep?
If you just want to delete the partition and there is nothing on it that you want to keep, try the steps below, otherwise ignore this response.
Go to a command prompt
Type Diskpart
when diskpart starts type list disk
locate the drive you want (a 2TB disk will show as a size of about 1863 GB)
select disk <x>, where <x> is the number of the drive you want
type clean
type exit
type exit.
Go into computer management. Windows should detect the disk as unitialized and ask you to initialize it. Do that, and then see if you can create partition(s).