Just to clarify what Terry said, there are three different versions of Mobile PC that you can buy.
1. Mobile PC with GPS20x USB receiver.
2. Mobile PC with GPS10x Bluetooth receiver.
3. Mobile PC software-only version.
1 and 2 only work with the exact receivers that come with them and no other. And I mean the exact serial number of the receiver that comes with it, not just that exact model.
The software-only version (3) will work with any non-Garmin GPS receiver and should work just fine with the Globalsat Bluetooth receiver.
If you have either 1 or 2 you will not be able to get the Globalsat to work with it.
I'm confused by your question about maps unlocked to the GPS18 and whether Mobile PC will still run.
Were you using the GPS18 with Mobile PC and did you add some additional maps to Mobile PC that you unlocked to the GPS18? Or were you using the GPS18 with Mobile PC and only the built-in Mobile PC maps? Or....??? Need more input.
...ken...