Why we need to protect our Computers?

Why we need to protect the computers? that's the question always questioning by my student. for some people maybe they computers is no need to protect, because they use the computer alone, nobody use the PC but themselves. But, how about if the computers is use by another person, or we can said the public computers, there must be any different kind of person who use the computers, some people understand how to use computers properly and some people don't (pure users).

If we meet this situation, I believe the computers really need to protect, but how? the effective way is we create few user log in and set it as limited access, so they can't change the setting of the computers without administrator permission. We can also password the PC, and if they are don't know the password, they can access the computer.

Probably this is only few solution from the thousand of solution if we want to protect the computers from physically damage, mostly the data damage. this is Inside The Computers who always give the best solution for our computers.