We are trying to replace old yellow glass with new glass on a window in our garage. We are having a problem trying to access the window. Any help would be appreciated. Hoping not to have to remove siding, but when we took the molding off on the inside of the window found nothing.

 

You have a removable stop on either the inside or outside... can't tell which from those pics.. (no inside pic). Generally if you can see which side the glass is "stuck" to, it's the opposite side that is removable. Most often on residential, it's stuck to the outside and the inside stop comes off. Commercial glass is just the opposite.

On aluminum windows, those stops snap on and are often difficult to remove. You have to start tapping on the edge of the stop with a sharp chisel or stiff putty knife, and be careful not to scratch the paint. Usually it's a matter of pushing in on the edge of the stop that snaps in and tapping on it until it starts to separate... then you run a thin putty knife behind it and carefully start prying it out. But you don't want to bend it or you're screwed.

 

Thanks! This really helped!