Sometimes it is necessary to use the SeaTools for DOS software to get the drive back to its native capacity. For example, if the drive is showing up as a smaller capacity in the BIOS (i.e. 137GB or 32GB) and it is a computer that should support a drive that large, then this would be a time to set the drive size.
Once booted from the SeaTools for DOS diskette or CD, the computer should display a screen with a license agreement.
If you get an OK message in white in the middle of the screen, then the process was successful. Remove the SeaTools diskette/CD, power off the computer for a few seconds, then reboot and check the capacity of the drive again in the BIOS.
If a message in red displays, then an error occurred. Make sure the drive is connected directly to the motherboard and not to a third-party controller card. If the drive is on a controller card then it is possible that the set drive size command may not work. Once it is connected directly, try to go through this procedure again.
Another option is to try a quick zero-fill from the main menu and then to try a "C - Set Capacity" again.