If you mean you entirely reinstalled the whole game, the only thing I can think of is that installing those modded files may have also made some changes in the game's registry files that need to be set back.
When I uninstall, especially large complex programs like games, I use an uninstall tool call Revo Uninstaller. It first uses the built-in uninstaller of the program you're uninstalling, then it follows up with registry and directory scans for leftover bits.
The best way to use an uninstaller tool is to first uninstall the program, install the uninstaller tool, then reinstall the program you're trying to uninstall. That way the uninstaller can see where the program is making registry entries.
Revo also has a "Hunter" mode though where you can navigate to the program's directory folder and manually enter the path of it if Revo doesn't have it in it's installed programs menu. Revo is also one of the few uninstall tools that has a free version, however it launches with a splash screen asking if you want to upgrade, but you can just cancel out of it and use the base tool.
Revo's biggest competitor, Ashampoo UnInstaller 8, has more bells and whistles, but they aren't really necessities. It also doesn't have a free version. A word of caution, it is best when using an uninstall tool to have it set to "Back up the deleted Registry items". Revo is set this way by default, and the setting for it is under the Uninstall tab in Tools>Options.
https://www.revouninstaller.com/products/revo-uninstaller-free/
If this doesn't work, try scanning for malware, because mods can sometimes have "hitchhikers" that cause problems. Malwarebytes is what I use and recommend,. It will install the premium version on a free trial basis, but then the base version is free to use as long as you like after that.
https://www.malwarebytes.com/premium/