I have a shower valve that will not completely turn water off. I know next to nothing about plumbing. Can I just go buy a new valve and change it or to I have to cut pipe and reconect pipe? Can anyone help me?
You should be able to change the insides of the valve itself and fix the problem. To replace the whole valve assembly, you would need to open up the wall and disconnect/reconnect via the supply lines.
Depending on the type of valve would dictate how the cartridge or washer/seats are replaced. Some are easier to than others to work on.
Does it have a brand name on it? Can you post a picture of it?