Best method is to use SYSPREP before uninstalling the MOBO --- (SEE HERE
This will remove all system drivers etc. and set it so that on the next boot it will rerun the analysis and install the new component drivers based on the new MOBO.
Another method is to run a REPAIR install
after replacing the MOBO which essentially does the same thing.
For either method you will need the VISTA OS disc so that it can find the needed drivers off of it and in most cases replacing the MOBO will require you to reactivate your VISTA Install since replacing the MOBO will deactivate the install (but just using the phone activation and entering the serial # from the system will reactivate it.