Problems with Illustrator files after installing plugin

Having error with illustrator. Copy&Paste became delayed, the All Swatch, Brushes and Symbols Tabs are mysteriously filled with plugin things that came from a file I downloaded in Freepik. I tried fix it with this given link but cannot be fixed, This 1st message pop up whenever I open file that has been infected. While the 2nd message pop whenever I'm trying to do my work in the [infected] file. : https://helpx.adobe.com/illustrator/kb/copy-paste-artwork-slow-or.html. I tried re-save my files into different names and in PDF format. Error bums Cannot be fixed. I tried update and revert to older version, cannot be fixed. I reinstall seems fine, but when I open some of my files again, the error returns. Seems like a virus that even infected my files from the original file from Freepik download. Video clip showing, whenever I copy & paste from my infected work file into a new file, that bug will infect the new file. [video]