They aren't bad movies. I own a copy of the DVD set and like them. They are just bad Conan movies. Arnold actually played 'Conan' in the Red Sonja movies, but with a different name.
I never read the books. But the first one was rather good. The second one however was too commercial. Especially the Conan swinging his sword to and fro just to look cool.
Conan has been the victim of adaption decay many times.