It's always helpful to supply as much information as possible. So, use the command "ls -l" on the directory that just won't go away and paste the result here.

When it comes to the rm command, -r means "recursive" and -f means "force" (as in, don't ask me about anything, just do it). If you actually are root (which is something else than to stand in the root directory, and still can't remove things with rm -rf it surely looks weird.

I have no idea why people use "sudo gainroot", just typing "root" with rootsh installed works, in my opinion, better.