Int 2F Fn DE00  - Desqview V2.26+ External Device Interface - Installatio  [Q]

   AX = DE00h
   BX = 4456h ("DV")
   CX = 5844h ("XD")
   DX = 4931h ("I1")

Return: AL = FFh if installed (even if other registers do not match)
   if BX,CX, and DX were as specified on entry,
       BX = 4845h ("HE")
       CX = 5245h ("RE")
       DX = 4456h ("DV")
Range: AH=C0h to AH=FFh, selected by scanning AH=DEh-FFh, then AH=C0h-DDh

Note:  the XDI handler should not issue any DOS or BIOS calls, nor should it
     issue DESQview API calls other than those allowed from hardware ints

See Also: AX=DE02h,INT 15/AX=5400h