WD external disk problems, error detected

Hi. Well, I have a problem with my WD external disk P/N WDBAAUA0010HBK-01 (1TB) The drive is detected as H Drive, but it said "H drive not accessible. The Parameter is incorrect." I checked on MyComputer>Manage and I formatted disk as I read on other forums as a solution. After formatting I didn't recognize any aprovements. As recommended I did a CHECKDISK, which I used TESTDISK.exe...