.. And if you don't follow the rules, your computer will kick back. Indiscriminate attempts to fix problems can lead to worse problems, so if you are not sure about something, ask first. The secret to computer happiness is to work within your technical ability. If you don't have any, keep it all simple.
It helps to have knowledge about how the software interacts with the computer hardware, and that is what this website is all about, understanding the basics.
Windows 10 is the new kid on the block, and is well worth having assuming that your computer and peripheral devices like it.
It is a mix of features from Windows 8 plus one old favourite, notably the Start button. I ran the test previews on my Toshiba NB250, a severely underpowered small notebook, and it worked really well, much better than Windows 7 ever did. It is now installed on ALL of my computers.
It isn't for everybody though. You may have a computer which is too old now to get decent support from its manufacturer, likewise some software, printers, scanners etc. Windows 7 will be supported to some degree until 2020, so there is no need to panic just yet.