The GPS is detected as a mouse during reboot
The problem happens sometimes when Windows recognizes a GPS data stream as a Microsoft BallPoint device that has just been connected to the computer.
The simplest way to avoid this problem in Windows XP and 2000 is:
1. Connect your GPS and wait until the mouse starts jumping.
2. Then, disconnect your GPS from the USB adapter, but leave the adapter connected to your PC.
3. Make a right click on My Computer.
4. Select Manage.
5. You will see a new window.
6. On the left side of that window, under Computer Management, click on System Tools to see the content and select Device Management
7. After that, on the right of the screen you will see a list of devices, select the one that says Mice and other pointing devices.
8. If here you see listed a Microsoft Ball Point Device, you have to make a right click over it and choose the option to disable.
9. This will mark that device with a red X, and will not bother you again.
10. Now you can close the Computer Management window making a click on the X at the top of the screen.
11. Reconnect your GPS and test it.
Please take into account that if you connect the GPS to a different USB port or hub, the GPS will be installed using a different COM port and you will need to repeat this process again.
This thread contains another tips on how to disable auto detection of a serial mouse: