[Elecraft] KXUSB problem

[Vic Rosenthal 4X6GP/K2VCO]

I have a W2 wattmeter which came with a KXUSB adapter. The KXUSB worked 
with an old XP computer, but I can't get it to work with my Windows 7 
machine.

This computer has two real serial ports and it already has two 
USB/serial adapters in use (both FTDI). When I go to the Device Manager 
it lists COM1, COM2, COM4 and COM6.

When I plug in the KXUSB it flashes, but no additional COM ports show up 
in the Device Manager.

The W2 software sees the same four ports, but of course doesn't find the W2.

Rebooting doesn't help. Does anyone have a suggestion of how to fix this?
-- 
73,
Vic, 4X6GP/K2VCO
Rehovot, Israel
http://www.qsl.net/k2vco/