|Yeah, do you physically connect a cable to your com port or is the GPS device a card you physically install?|
If you connect directly then go into your cmos/bios setup and see if you can rename the com port as com2. If so you may need to disable 'PnP OS' (if that's an option) to keep windows from changing it back to com1. Your other option for a direct connection is to buy a PCI com port card.
If it's a card then the installation software should create a virtual com port somewhat like a modem does. In that case you shouldn't have to do anything but install the drivers and software.
Now that's what I call a sticky situation