Dell W2606C 26" LCD - seems to have lost horizontal hold?

Channels (cable input) now show in b/w only, and the image is badly twisted horizontally, plus I can see the normally hidden bar at top/bottom. Reminds me of old TV's with horizontal hold shot.

Same thing with Svideo input from a DVD. In both cases, sound is fine.

The Dell TV menus display just perfectly though. They are NOT twisted, and they are in color. I have done "factory resets" and physically unplugged it, but no change.

Way out of warranty, so any help appreciated. I presume there is no more hidden knob to adjust this.

Thanks.
John