I actually considered not putting that in.. as I was sure someone wouldn't ask for a specific example lol. But windows generally speaking, never seems to have been good a managing memory (doing garbage collection), and just by installing/uninstalling leaves a lot of crap on the system that seems to slow it down over time. I don't really think it should be this way. I know it sounds daft, but I think the install of applications is 'too' intwined with the O/S itself.
For me, there really isn't an alternative to windows however. If I want to play games I have to use it, and I'm used to it, and generally I like it.