Newest versions of software are not always best. It's always been that way. For instance, Windows ME was worse than the previous versions. I use *nix systems and the newest version of one of the programs that handles input on my machine brings it to a crawl, so I haven't updated it. Game updates don't always work out well, either.
So, I'd try 295.1 or 295. I'd also check your Python installation, as something may be amiss there. And just to make sure, you shouldn't be installing in Program Files on the C drive.