I have a 47" Vizio M471i-a2 TV. The sound stopped working and the TV isn't responding to the remote or the power button on the TV itself. This has happened in the past and was easily fixed by unplugging the set and plugging it back in. Unfortunately, this no longer works. I called a repair shop and they quoted me at $300 to fix it (about half of what I paid for the set). What could be causing the TV to not even respond to the power button on the set and is this an easy fix? I really don't want to spend $300 to fix a TV I've only had for 2 years. Any help would be greatly appreciated!!