Operating Systems

What happens when you boot your computer?
Do you you always communicate with your computer by clicking on icons?
Are there some still some command-line features on newer GUI-operating systems?
I still have Windows 95. Why would I want to upgrade to a newer Windows version
What are Windows patches
Why would you want to have an account without administrator rights on your private PC?
What are the best features of Windows XP over earlier versions?
What are some good features of MacOS?
What are good features of Linux?
Would you use Unix for your private PC? Where is it used?
Could you run Windows on a Mac? Could you run MaxOS on a PC?
What happens if you run several programs at the same time?