OK, I will offer one more post on this problem. And no one questions your knowledge about computers, it's just that you are an Apple novice. As we all were at one time. Different platforms do things differently
Go back to the advice that Baltwo gave you. Although you think you followed his advice, I don't think you actually did. He told you to remove the two Dock Preference files from your Users Library, place them on the Desktop, then Log Out and Log Back In. You said you only found one Dock Preference file, not two. And it didn't help.
At this point we don't know if it will help because you entered the wrong Library. You entered the System Library and you want the Library for your home folder. Open a Finder window and set it to the Column View. Click on your Home Folder (the little House thingy) in the sidebar. Then click on Library and then Preferences. Scroll down to the 2 com.apple.dock plists and follow Baltwo's instructions. When you remove a plist from the library, the next login causes a new, pristine version of the plist to be created.
Who knows whether it will help, but this is basic level troubleshooting. You may want to look up "Creating a new user account" in Apple Help. That's another basic troubleshooting tool.
Good luck with OSX. Once the kinks are worked out you're gonna love it.
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