How do you shut off the water from the valve behind the toilet..i keep turning it but it doesnt appear that the water is turning off??? it just turns and turns??

1.) Check to make sure that the water shut-off valve is all the way open (the water valve a.k.a. the shut-off valve is located behind the toilet near the wall or the floor, depending upon installation placement.) The water supply line attaches to it and feeds up into the refill valve assembly inside the toilet tank.
2.) Check the float assembly or the refill valve assembly, make sure it hasn't bound up by getting caught on another part inside the tank.
3.) Check the water level to make sure that it sits about 1 inch below the overflow tube in the middle of the tank. If the water is lower, adjust the float inside the tank to raise the water level. For models that have a ball float, turn the screw on top of the fill valve clockwise to raise the water level. For models that contain a cylinder float valve attached to the fill valve, squeeze the clip on the side of the float and pull the float up until the water reaches the desired level.

IF the water wont shut off with the valve that is under the tank then you have to shut off the water to whole plumbing system.

Yes, IT may also be a faulty trigger as well, if you can, manually activate the trigger and verify if there is a shut off.

It sounds like the fill valve is not operating correctly. Remove the fill valve which it the tall item inside the tank where the water runs through and replace it with a universal replacement part from your local hard ware store. Take the valve to the store so that you can get the proper replacement piece.

turn counterclockwise , the shut off valve
must be behind the toilet . 14 inches high from the floor

Remove the top of the water tank.
check to be sure that the flush cover (about in the center of the tank) can close all the way. It seats into a 2 inch hole - and must seat all the way around. If it fails to seat, then the fill valve (on the left side of the tank) will continously let water into the tank.

As a starter experiment, you may try just turning whe water off at the wall shut off. Then inspect the tank to confirm that it is losing water.
If confirmed, then the above solution is correct.
If it is not losing water, then the fill valve is faulty and will need to be replaced (it is allowing water to over flow into the "OverFlow" tube.....

I recommend that you keep the water turned off at the wall until the toilet is needed - and the problem is repaired.

If there is no water on the floor then the water is leaking down the main tank drain. Take off the tank lid, turn off the water supply to the toilet. Fllush as much water out as you can. Look at the main drain, sometimes if the flapper valve is connected with a chain, the chain can get caught between the flapper valve and the drain hole, the flapper valve is pliable so it tries to seal around the obstruction but can't always do it. Make sure there is obstruction, that the flapper valve is not out of shape or old and non-pliable and that it lines up with the drain hole and doesn't get "hung up" on anything.

for the upstairs if the valve is fully on there is not much you can do other than replace water service to the house or heaven forbid repipe.Valves usually don't restrict fill volume.But you can take the supply loose from the tank and stick it in a bucket turn the valve on and check the flow.this should narrow it down.Down stairs repair or replace flush valve

No problem on this one. Turn of the valve to the toliet just above the floor next to or behind the toilet. Go turn on a outside faucet. Is there still pressure? Wait a minute if it seems like there is still pressure to let the line pressure go down, what this is just water in the line left over. If the water stops on the outside faucet then the water is off. If you do not have a outside faucet then use a tub or a sink faucet. (if it does not stop then see part 2)....Keeping the toilet valve off remove the supply line from the toilet where it connects. This sould be the larger end. Is it is a flex line this should make it easyer. If it is a hard line like copper tubing, stop and go to the hardware store and a buy a flex supply line. This will make your job a lot easyer. After you remove the part of the line that connects to the bottom of the toilet then find a bucket place the end of the line you removed from the toilet into the bucket ( you may have to place the bucket at an angel to do this. Now turn the water valve at the wall for the toiel back on and drain the line. You may have to empty the bucket a few time but the line sould drain out.

( Part 2) If the water to the house is still on you need to go to the water meter and turn of the curb stop, this is going to be the valve inside the meter box ( if you do not have a well) and are on public water. You will need a cresent wrench, sometimes these valves can be hard to turn so you may have to use a little force. If you are on a well the you need to find the valve in you well house and turn it off. If you need more help or this did not solve this problem the repost and I will check back in a little while.

When facing the valve turn it clockwise to close. As always procede with caution.

Please rate this response and good luck, Phil