I have an older bathroom. It is one of those 3 handle ones, (hot cold, and the middle handle to switch it from shower/tub).
It drips alot. Had been able to get it to stop if I turned it off just right, and switched it to the shower. Now that doesn't work and the drip is almost like a stream. Any quick fixes for this? I know in the past, I had the same problem and it was a melted o-ring.

Barring that, is there anywhere I should look in my condo or bathroom for a water shutoff? I know there is one in here, but can't for the life of me remember where. Is it possible it is behind the drain switch on the tub? The thing that either lets water drain or build up in the tub?

P.S. the drip is cold water if that makes a difference.