Upon bootup, Windows XP will sometimes detect the laser rangefinder as a Microsoft serial mouse ( MicrosoftKB article) - that has happened if you see the cursor jumping all over the screen with context menu and selection box popping up at random. Here are the steps you should take to fix this problem:

• Download the following file and extract comdisable.exe into a directory of your choice: microsoft_comdisable.zip
  Note: comdisable.msi is an installer that simply extracts comdisable.exe and readme.txt into C:\\Program Files\Microsoft COMDisable, you can also get the installer directly from Microsoft
• Next, from command prompt navigate to the directory where comdisable.exe is located:

• You may view the available serial ports on your computer by issuing a comdisable /list command

• You will see a listing of all the serial ports together with their status - enabled or disabled

• To disable a port, type comdisable /disable COM#, like in the example below. Note that the port won't be disabled until you reboot the machine.

• If you issue a comdisable /list command now, you will see that the port you just disabled has its status changed to “disabled”

• Repeat the comdisable /disable COM# command for all ports you want to disable. Since comdisable only stops Windows from scanning serial ports in an attempt to detect a mouse, it's a good idea to disable all ports - the ports will still function, you just won't be able to use a serial mouse.

• comdisable /list should tell you now that all ports have been disabled. At this moment reboot the machine for the changes to take effect.

Here's Microsoft's knowledge base article about the COMDisable tool: COMDisable