What would be the best way to hang about a 40 lb. framed mirror? Should I find the studs in the wall or use a picture hook without finding the stud. I read something earlier that someone said you could use picture hooks and I couldn't tell if they meant you had to use the studs or not. Anyway, someone please tell me the best way.

It's best to find the stud but if it isn't centered where you want to hang the frame, use an insert or a toggle. They fasten in to grip the back of the drywall. Then back the screw out just enough for the picture wire to hang over it.