Using my Plasma Television as a computer monitor

Just going from experience. When installing U-verse and watching a ghost of a news announcer on all screens, one has to wonder.
Never do I ask how old a customer's components are, except once (different customer) when their remote had 5 buttons and a wire to the TV I had to ask.

I would just use a VGA to DVI connector, you can find them in the computer cable section at Best buy or Frys.. it connect to your desktop as VGA and tv/monitor as DVI. I had to get one for my friends old server computer for when he wanted to do updates he could just swap to that input.