How to set Nikkor 50mm 1.8 lens to manual?

I'm using a Nikon D80, I just got the 50mm a month ago for sharper images, but the autofocus on it is very very slow and sometimes just refuses to focus on anything. I can't find a manual setting on the lens and i've tried using the manual setting on the camera but the lens still autofocuses, how can i stop this? Or at least improve the autofocus

There's no autofocus "button" on the lens or in the camera menus. It is a switch on the camera that says "M" and "AF"

Switch is to "M"

With early designs of AF lenses, Nikon used in-body autofocus. This means to deactivate the autofocus you need to switch the AF/M switch on the left of your camera body.

Only AF-S and AF-I lenses have switches on the lens.

Switch the focus control on the CAMERA to M (note: this is not the same as setting the camera to Manual for epxosure!).It should be a three position switch somewhere on the camera body, labelled C, S & M.