How do I disable mouse detection on a COM port (for UPS usage)?

A. Follow the steps below after first removing the UPS from the computer

  1. Start a command prompt (Start - Run - Command)
  2. Move to the boot partition
  3. Change the attributes of boot.ini so it can be edited
    attrib boot.ini -r -s
  4. Edit the file (edit boot.ini) and for each line with multi(x) (for IDE) and scsi(x) (for SCSI) drives add at the end
    /noserialmice=comx ----------------------- where x is the com port number
    Exit edit
  5. Set the permissions back on boot.ini
    attrib boot.ini +r +s
  6. Shutdown NT and power off
  7. Attach the UPS
  8. Boot the machine and start NT, and NTDETECT will no longer try and search for a mouse on that com port

The /NoSerialMice switch only disables the Microsoft Serial Mouse device driver.

If you have installed any third-party mouse drivers, go into Control Panel - Devices and disable their Serial Mouse drivers as well. For example, if you installed the Logitech Mouseware V8.0 for a Trackman Marble, you must also disable the "Logitech Serial Mouse" device, called "lsermous" (note that the Arial lower-case l looks like a capitol i).

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