Can not remove Lexmark printer drivers from a Vista machine

Hi

Some people I know have bought a new PC which runs with Vista. They decided to install all their old equipment etc

everything worked fine apart from a lexmark printer/scanner ... they installed the drivers from CD and the installer crashed.
then they got a notice saying "successfully installed..." but they can't see the printer through the system!?

anyway I tried to uninstall it to install up to date drivers.. but the uninstaller keeps crashing.
and the installer of the newer driver won't remove the old drivers it just keeps saying "previous driver has been found please remove it"

so my question is ...
Where/how can I uninstall these drivers? can I just run a registry cleaner etc
and where does Vista store its drivers?!

thanks for reading and thanks in advance

Will

Did they check to see if the printer is compatible with Vista?
What is the model number of the printer/scanner?