My Vizio E370VL is not accepting its Native Resolution from my PC through HDMI

My Vizio E370VL is not accepting its Native Resolution (1920 x 1080 x 60 - 1080p) from my PC. In fact, the only two reliable resolutions it will take are 480p and 576p. When I initially set it up, it worked fine, but it just quit out of nowhere a couple of days later and went to a black screen and stated "Not Support"(I wasnt even actively using it at the time - it is my 2nd monitor). After tinkering with it a bit, i got it to come back on by powering down both components, only plugging in the HDTV and TV (not my Samsung 226BW monitor) and using it as a primary screen. It booted up fine, and I switched it to my secondary screen after plugging in my monitor. It stayed on for about 15 minutes before it comes up with a black screen and stating "Not Support" again.

I am almost certain it is not a Graphics Card Issue, I am worried that my TV is having issues handshaking with my card though. Is there a firmware download available for my TV? I couldnt find one. Does my TV just suck?

I am using a nVidia 9800 GTX+ with a DVI to HDMI adapter and a Monster Cable HDMI. My card is fully updated, cable works fine with XBOX 360 on 1080p. Was able to play Starwars The Old Republic for some time on the HDTV without any issues. Watched an 1080p movie fine also.

I have searched everywhere and cannot find an answer, or even a case similar to mine. In other cases that were close, it would NEVER accept the resolution not intermittently like mine.

Please help!
Thank you for all of your responses.