This is the wrong place to teach about computers and networking, but I can address a few specific points. There is a lot of misinformation and erroneous assumptions here. I will try to write in a way that everyone can understand, so I ask technical people to be forgiving about "simple" terminology.
* Once a Hacker Knows Your IP Address...
is wrong. If a hacker knows your IP address, they should not be able to get into your computer, period.
Hackers are constantly scanning and attacking your IP address; you are unaware of it. In the past, whenever I had a friend who was expecting a baby, I would "open a port" on my internet connection and collect all the usernames that they tried. I ordered the list by numbers of attempts, and gave it to my friends as baby name suggestions, reminding them not to name their baby "root", "admin", "test", or "postgres" which are usually near the top of the list. The last time I ran it, Cyrus, Richard, Michael, Cary, Mike, and Carlos were the most popular "real" names the attackers tried.
-> IMPORTANT: I did not do anything to indicate that the port was open. The hackers found my IP address and noticed the open port on their own. It would take only a few days to collect the names from hundreds and sometimes thousands of attempts.
The "other" operating system is called Linux, not Linus. (Linus Torvalds is the person who invented Linux). Linux is free for all to use. There are thousands (millions?) of free programs that you can run on Linux, and many of them have similar features to their commercial counterparts. I won't try to name matching equivalents for GeorgeC's list. For examples, LibreOffice is a popular replacement for Microsoft Office, and GIMP is used in place of Photoshop. Acronis runs on Linux directly, but there are freeware backup solutions for Linux too. One major exception is US tax software, but fortunately the major tax software companies offer online versions that you can run from nearly any browser, including the one that comes with Linux (usually FireFox).
You are already running Linux and don't realize it. It is everywhere. It is in nearly all of your appliances. The Android operating system in your phone is based on Linux. Most websites run on Linux servers, not Windows, and that probably includes this one. The list goes on.
-> If you are struggling with Microsoft Windows, then Linux is probably not for you. There is definitely a learning curve, and it will be confusing at first, like any new thing. Still, if all you do is basic stuff like web browsing, email, word processing, spreadsheets, etc., then Linux could be the answer for you. I would search for something like "Getting started with Linux" and try to avoid being overwhelmed with options and details.
I am not sure that I would agree with assertions that Linux is more or less secure than Windows. That's a debate for a different forum. What I will say is that WHATEVER operating system you are running, you should keep it current.
* I Don't Visit X-Rated Websites, So My Vulnerable OS is Safe. I Never Had a Virus ...
If you are running an unsupported operating system and using the internet, then you are not safe. I wonder how anyone can feel certain that their computer is not infected, despite whatever third-party products they may have installed. Everybody starts out telling me that their computers are clean and safe. I have some small experience in this area.
Sorry, but I have to go. I hope this helps.