Is it just me or do computers just seem to have minds of their own????

I am the type that needs to know the why, where, when and how on things! Sometimes that is not a good thing. I will find myself looking for a reason on why I see a certain file that I know didn't come from my doings.....Most times I hit a wall. But then there are those times when I do find that I have caught onto something interesting. I am on 3 social networks and play a lot of the games. So friends lists grow huge and rapidly. That is also always not a good thing! But I feel that if I can keep my computer safe and put up the defense so that no one or nothing can do harm, then I should be able to have what I want and how much I want on my computer. After all....It is MY computer!!!