Do you have the remote?
Sorry if you've checked all these things already. Just trying to be thorough. :-)
With the TV on, use the remote to control it. There should be a "Menu" button (or similar) that should bring up the controls for the TV. (It shouldn't care if there's any input at all to get the setup screen.) Alternatively, there should be a "TV/video" (or similar) button that lets you cycle between the various input ports. You might need to move it off channel 3 too.
I assume it's something simple like the TV's expecting input from the cable box that isn't there. It would be strange for the TV to fail exactly the same time as the cable leaves.
If you've got the manual for it, check that. :-) Samsung's web page ([link|http://www.samsungusa.com|http://www.samsungusa.com]) doesn't seem to have any info of use. Sams Photofact ([link|http://www.samswebsite.com|http://www.samswebsite.com]) doesn't have anything for it either (they have schematics and repair manuals for lots of stuff).
One final thing - perhaps the cable guy was too rough. Maybe he did something that caused the video input to become disconnected. If you can carefully remove the panel where the video input connectors are and check them you might get lucky. But I really think it's a setup/software configuration issue.
HTH. Good luck!
Cheers,
Scott.
