FMS won't run, too many com ports?

[uselessoldfool]

FMS runs fine on one of my PCs, but it cannot be run on the other. Probably not an FMS problem, but I need some guidance...
The problem is that when I install the USB driver, it creates a new com port. Unfortunately, it creates com port 7, and FMS control setup only allows for 1-6. XP device manager shows only 2 com ports installed, 1 and 7, and the USB controller interface is assigned to 7. How do I get rid of the apparently hidden (or non-existent) com ports 2-6?
I even tried deleting com port 1, hoping that a USB driver remove/reinstall would take over #1, but it STILL installed as com port 7.
Where do I start looking?