Return a count of the hard drives on a system.
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 Syntax

        GT_HardCnt() --> nNumberOfDrives

 Arguments:

      None.

 Returns:

      The number of physical hard drives fitted to a machine.

 Description:

      GT_HardCnt() can be used to check the number of hard drives fitted
      to a computer system.

 Examples:

      ? "Hard drives on this system =",GT_HardCnt()

 Source: HARDCNT.C

 Author:  Dave Pearson