Here is a driver for XP.
http://www.downloadtube.com/Drivers/PRINTER/Canon-MultiPASS-C75-MultiPASS-Suite-xp-download.html
If you enter the F8 menu when booting and disable Vista's driver check
feature, it might install and work properly on Vista. If you decide to try
that, be sure to set a system restore point and back up user files before
trying. A complete backup would not be a waste of time.
The _BIG_ problem with this is that you will have to disable driver check
each time you boot for the driver to load. That is not a good idea because
it compromises system security.
Since they appear to have a working XP driver (I have not tried it), it
seems a pity that they, Canon, did not take the extra step of making the
slight driver file modification needed for it to be usable by Vista. Perhaps
they will yet.
Just my view.