General Cycling Discussion - Need Some Help

I am new here and need some help. I have a kind of piece of junk Murray bicycle that needs some repair. I use it to get around at horse shows. If I did any serious riding then I would trash the thing but since there is a good chance of it getting stolen at the horse shows I don't want to put a lot of money into a nice bike. Does anyone know if Murray has a website? I have done a search and come up with nothing.
The chain keeps coming off. I was hoping I could fix this myself so I wouldn't have to spend a lot of money.
Thanks for any guidance you may have.
Ally

You don't say if it comes off the front gears are the rear ones, but it doessn't really make any difference, the fix is the same. There are two small screws on the derailleurs that control the distance that the chain travels. Check in the Mechanic forum for the Barnett manual and read what it says about the adjustment. It's a very easy fix you can do yourself.

I'm not sure Murray is still in business. The parent company was: GARDNER.

Thank you for your help!
It is coming off the front chainring. I did not say in my first post but it is what I would call a single speed bike - no gears. The manual that came with my bike mentions the screws that you did but I cannot seem to locate them. I am not even sure this is the manual for my bicycle.
I will check again tonight and see if I overlooked them.
I guess this is what you get when you buy a Walmart clearance bicycle.
Thanks again.

If you have a single speed there will not be any screws. How loose is the chain? You can tighten the chain by loosening the rear wheel nuts, pulling the wheel back and retightening. You want a little slack in the chain, not TIGHT. The bottom bracket could be loose as well(The crank will wiggle) You might want to go to a bike shop to get that adjusted.