80-200 mm lens not responding

I recommend the following steps: Start with a fully charged battery. To eliminate that it could possibly be the lens, do you have another AF lens you can attach? Is the AF/MF focus which turned on to AF on the lens? If that other lens works this is your answer. If the other lens also does not respond then it is a camera issue. Any error code displayed? On the back of the camera, right side to the display, look for the quarter round button labeled AF. Check/set the desired AF operation. (Press the left right keys or turn the dial to select the desired AF operation, then press the set button) Check your AE lock button as well. Lastly, if all fails revert to camera default settings (Select: the wrench symbol tab, select: clear all camera settings) If it still does not work it is possible that there is a defect. Reference manual: http://gdlp01.c-wss.com/gds/2/0300014592/03/eos-rebelt5-1200d-im4-en.pdf

As soon as the camera is switched on, the lens barrel will come out. Everything should be ready to shoot pictures. If it is not responding to the buttons, you could try to remove the battery for a few moments. It will cause the camera, to start from scratch. Call it a cold boot. But then after switching on, it should respond normal, like you used to work with it. If it stays frozen, visit your dealer or contact a Samsung certified repair centre.

Your lens is not communicating with your camera, which could be a result of unclean electrical contacts on the lens. Just wipe the electrical contacts that you see on the lens with a dry cloth to remove any residues on them and try again. If this doesn't work, you may need to contact service personnel.

This camera focuses the lens by sending an electronic signal to it. If you hear a clicking sound, the lens is receiving the signal, but not responding. I suggest you take the camera & lens to a local photo store & ask if they could let you mount another lens on the camera to see if THAT one works; if so, the problem is with your lens. A repair might cost as much or more than the purchase of a new lens (I'm assuming you have the "kit lens," which is the 18-55 mm lens) -- Amazon.com offers this lens for $100.
This is a wonderful camera; I use this with the same lens, and the D7000 with a larger zoom so I don't have to change lenses in the field. It's simple to use, does a great job. Only drawback I find is I can't use it with the older auto-focus lenses that need the focusing motor in the camera instead of the newer ones that focus in the lens, as yours does.
Probably worth repairing if it's the camera, but it sounds to me as if it's the lens that's giving you the problem.
Hope this helps!

If it works Ok in manual focus Replace the broken ribbon cable in the lens

thats because its not a very good lens or its very dirty,,,tre looking at the light reading and shutter speeds with a similer lens fitted then put on the zuiko and see the difrence

Switch to M (manual) mode.

Try a reset (hold down both buttons with green dots next to them) and see if that helps.

Also try cleaning the contacts on the lens itself (light rub with a pencil eraser usually works well).

You should not try to manually retract lens because lens has few gears in loading mechanism that can be broke if you put some force in try to rotate on lens.

I have a D50 as well but never experienced this problem. One thing to check as you already mentioned are the metal connections between the lens and the camera body. Make sure they're clean and shiny. Another thing to try would be switching between AF and MF modes on the lens itself.