How do I get rid of the owner screen?

Or the constant lua errors whenever I open up the spawn menu that says

ERROR: GAMEMODE:‘OnSpawnMenuOpen’ Failed: gamemodes\sandbox\gamemode\spawnmenu\spawnmenu.lua:63: attempt to call field ‘SpawnMenuOpen’ (a nil value)(I would post a pic but my proxy is broken so I can’t upload a picture)
Or the chat message “This server runs PC-Mod 2!” (without deleting PC-mod 2)

Delete all your addons, and find the lua file with the chat message in.