The Bios *could* have a power management mode, APM maybe?, but being a brother PC, that has to be older. I am not sure on the BIOS settings, but worth looking into.
Depending on how much disk space the Brother PC has, maybe you should copy all the setup files (*cabs) to a folder on the HD, then run the install from there. it might speed installation up some.
Are you installing via floppys?