Note for Windows XP users:

Some XP users have reported that if a GPS is plugged in to a serial port whilst XP is booting, the mouse pointer jumps all over the screen. If this is the case you may have to do the following:

bulletUnplug your GPS from the system
bulletDisabling serial mouse devices by doing the following:
bulletRight click My Computer
bulletSelect Properties
bulletSelect Advanced Tab
bulletSelect Settings in Startup and Recovery
bulletSelect Edit
bulletadd /NoSerialMouse (this is case sensitive so add it exactly as shown here) to the line that looks like:
multi(0)disk(0)rdisk(0)partition(2)\XP="Windows XP" /fastdetect
so that it now reads:
multi(0)disk(0)rdisk(0)partition(2)\XP="Windows XP" /fastdetect/NoSerialMouse
bulletFile -> Exit Save yes
bulletand reboot
bulletOnce rebooted re attach your GPS.