I'm hoping someone has an idea of whats causing this and/or has a solution.

I have a D600 which in this case is being used as a wardriving machine while I'm on the road for work ... I have a Garmin eTrek GPS unit that plugs into the serial port on the back (com 1).

But when I plug the GPS unit into the serial port (with no other programs loaded outside of Windows XP itself) the mouse starts freaking out ... jumping around the screen, mostly in the bottom right corner, but it will jump all over.  If I unplug the serial cable it stops.

Now, with the serial cable unplugged I go into Netstumbler and it tells me that the Com port is in use by another program (which can't be right since nothing else is open).   If I close Netstumbler and go into to device manager and change the memory address for the Com port all the problems go away.  Apparently the default memory address causes that for some reason.  But I have to change this every time I start the computer when I want to use the GPS.

What could be causing this to happen?  I had the IR port on the laptop set to com4, but I disabled that (which didnt help), I tried setting the serial port to be different com port numbers in BIOS which didnt help.  I checked the computer for spyware and virii, nothing found.  I checked the programs in the background and there is nothing that uses the com port in there.  *shrug* 

I have no idea ... anyone have any ideas what the root cause of this might be?

Thanks in advance,

~Matt