Thanks for the answers everyone.

Dougf8, I have tried manual everything, to no avail. No auto focus or A mode. I could get a cheap MF Pentax off eBay to test if that would work, then?

Ken, I did not see anything to reconnect, just screwed it back on. Twice now

Peter, I do not know what happened to the camera. It was going to be thrown away, I saved it. At the very least, I will sell it on eBay for parts and get something...

Hi everyone. I am new here, just registered as I am trying to find out how to fix this K20D that I was given by a friend who was going to throw it away. When he gave it to me, the mount had come off and was attached to the lens. I screwed the mount properly back onto the body. The camera will take a picture no problem without a lens attached, (just white of course) but when I put the 18-55mm that I have on it, it can see the f/stop, but the exposure numbers just flash on and off, and focus will not work, depressing shutter renders a big fat nothing! I have tried the lens on another camera, works fine. Any ideas for me? Thanks!

Daniel C