For many reasons I want to go back to a default forum, I removed some mods trough the Admin Panel but there is some mods that don't show and some that "uninstall" ain't working. Is there a way to erase them all or any files that I could simply upload and that wont have the "bad" mods?
Download a clean install of SMF, and replace all the sources and templates in the clean install in your current FTP. :)
Done that and I still have all mods there.
Do I have to do some thing else?
All your modifications will be removed when you upload clean sources/template files etc.
Final step would be to remove the database entries. Post a link to your forum if the board is not restored yet.
Odds are some files did not get replaced.