I am establishing multi-site for that latest version of wordpress. I acquired 2 or 3 plug ins all messed up after i up-to-date it and I must remove the files and database info by hand since the remove function in wordpress is not working. Where's wordpress plugin data based in the SQL Database, among the plug ins had its very own table(s) which i dropped, however the others don't.

There's no generic answer, every plug ins will vary.