Just FYI. The last full installation of the game I did was about 10 years ago.
However, people that use anti-xxx software, some type of security software, something to control what programs run in the background, or just about any software that alters the original operating system installation (save Microsoft updates) has the chance to bork any game installation that makes use of online patches to update the software.
More often than not, software crashes are the problem. Due to all the things the game "remembers" there will always be a chance for borking up "settings" files in the advent of a game crash. That is the only folder that has any real chance of getting messed up.