Planar 2611W flickers and/or goes black; LCD component issue? Possibly videocard?

I bought a Planar 2611W 26" 16:10 monitor in 2009.

I have been using it for years, and it is a very nice monitor with low black level and good contrast.

In the past year or two, I have noticed a progessively worsening flickering problem. Sometimes it will flicker for a second, and then stop. Sometimes it would show a loss of correct coloring, and I had to reset the resolution to make it go away. But, it would always go away after a moment.

Recently, the monitor has started to flicker and then completely shut off. The buttons become unresponsive, and I have to unplug the monitor and plug it back in. Then it works fine until the next time it starts flickering, which could be minutes or hours. It is unpredictable.

My question to the hardware experts is: What component is damaged or broken that causes this problem? How can I diagnose the source of the flickering and shutting down? What can I do to fix this?