Water shut-off valve

[M F]

Hello,
Here is a picture to the water valve shutoff for my house:
https://imgur.com/AhbTqfw
I need to turn the main water valve off and I can't seem to be able to locate it. I turned the screw pointed to by the green arrow until it was all the way against the pipe. When I initially approached the valve it was opened about 5 turns. What does this screw do? The other possibility is that the red arrow is the shutoff valve. It's curious that the red handle is disconnected from the valve and is on the floor. Do I need to reattach it? Could someone help point me in the right direction. Thanks for helping a beginner!

 

[Geofd]

the red one is the actual shut off the handle is on the floor below it the other is a pressure regulating valve and yes you would need to at least fit it back on the stem

 

[M F]

the red one is the actual shut off the handle is on the floor below it the other is a pressure regulating valve and yes you would need to at least fit it back on the stem

Thank you for the info! I didn't notice any difference when the screw pointed to by the green arrow was all the way against the pipe or out about 5-10 turns. Should I leave it like I found it or does it matter?

 

[Geofd]

Thank you for the info! I didn't notice any difference when the screw pointed to by the green arrow was all the way against the pipe or out about 5-10 turns. Should I leave it like I found it or does it matter?

leave it the way you found it....

 

[Diehard]

FYI...Turning the screw on the pressure regulating valve clockwise (into the pipe) increases the pressure setting and vise versa.
If you say, "5 to 10 turns", I'd suggest you consider getting a pressure gauge to find out just what pressure you are changing it to.