In order to show a list of Drives We needed to get the name of the Drive. The following API call gets the volume name as well as the serial number.

Create an NVO add the following local external function:

function long GetVolumeInformationA( ref string ls_RootPath, &
 ref string ls_VolName, long ll_VolLen, ref string ls_volserial, &
 long ll_maxcomplen, long ll_systemflags, &
 ref string ls_SystemName,&
 long ll_SystemLen ) Library 'kernel32'

Then add a function called GetVolumeName which accepts a string and returns a string and add the following code:
// Call the API function to get the volume label from a drive letter
Long ll_Max, ll_Flags, ll_Ret, ll_FileSys
Long ll_Vol
String ls_Vol
String ls_Drv, ls_FileSys, ls_Flags, ls_Serial


ls_Drv = as_Vol
ls_Vol = Space(32)
ls_FileSys = Space(32)
ls_Serial = Space(32)
ll_Vol = Len( ls_Vol )
ll_FileSys = Len( ls_Filesys )

ll_Ret = GetVolumeInformationA( ls_Drv, ls_Vol, ll_Vol, &
  ls_Serial, ll_Max, ll_Flags, ls_FileSys, ll_FileSys )

IF (ll_Ret = 0) THEN
  ls_Vol = ''
ELSE
  ls_Vol = Trim( ls_Vol )
END IF

RETURN (ls_Vol)

Call the function passing the drive you want the volume name for. For example C:\