A ltitle bit more info would be helpful - like what kind of problem you are having with the game.. and what video card you are using and what driver versions. I have heard/seen a lot of reports of problems with nVidia drivers and Fable (well nVidia drivers and Vista in general really)..
You can look at trying a couple things:
* Get a different video card (ATI generally seem to have more stable drivers under Vista at the moment)
* Try pushing your graphic detail settings in game all the way down
* Find out if there are newer/different driver versions out there and try them.
Also, please see the other thread about this already.. if you hare having the same symptoms, let me know and we can merge the threads.