Legate, if you remember, a few months ago I had the same problem when I updated to Patch 28 (like Tobin's, but you PM'd me about it instead). Recently I updated to the latest consolidated patch, and had the same issue after I played the game twice with no problems (leading me to believe the Vista issue back when I last visited was fixed... =P). HOWEVER, this time, neither of the three steps worked! I tried downloading the patch again and recopying it again and again, reinstalled .NET 3.5 SP1, restarted windows... To no avail. I did exactly what you told me last time as well (numerous times), but each time I started there were issues with loading previous saved games. Funnily enough, I can still create a new game (I haven't tried to save it so I'm not sure what's wrong).
*utterly confused*