Good advice, but I'd like to point out that even Apple and Linux users run into the occasional problem.
You may have already done a search, but I did find this article
that might help. You would have to do that with each of the apps that you want to get rid of, so that could be a long process.
Don't forget to back up all of your documents, pictures and other things you will want to keep! This might be a good opportunity to do now anyway, since you still have access to all your files. That way, if you do need to wipe the system, at least you'll just need to reinstall the programs you want to use. Don't forget to copy any saved game files you'll want to keep as well (which is one of the reasons I love Steam's Cloud Save feature