My serial mouse insists on installing on Com2 even though the settings are correct for com1. How do I fix this

In my experience try disabling the com port you don't want to use in BIOS settings. If you disable COM2 in BIOS the mouse may use COM1 or 3 but it should work better. This trick also helps when a Modem is installed and takes a resource. Disabling all COM ports in BIOS gives you the options to setup stuff in Windows manually.
Roy