Is it actually pairing, and reporting as "paired"?
If you go into Control Panel - System- Hardware - Device Manager, does the GPS appear anywhere? Is there any error message?
Take a look there in Ports (COM & LPT) to see what it says about COM7. I had terrible trouble with a Bluetooth dongle that added another batch of COM ports every time it was plugged in. The software was looking for it on COM8; it had got to something like COM96 when I finally went into "proper diagnosis" mode.
You might need to turn on "View" - "Show hidden devices" to see all the COM ports that have been allocated, if they aren't connected at the time.