Security issues I.

Security ! It's a very important thing that people are interested in all the time from the beginnings of their being. Their interests range from personal security over tangible property security to intangible property security (currently it is mostly intellectual property).
At the present time we use personal computers on a daily basis as a helper (or assistant or aid) in work and also at home. So there is much information stored in computers' internals and the most of it is very important for us. And some information is confidential. But hardly anybody is aware of this. We find the true value of our property at the moment we lost it - or somebody takes advantage of it. (It is similar to our interest in our tangible property.)
I know that it is well-known truth, but when I see what the computer users can do and can't do, I am not so sure about it.