GeForce 9800 GT not detecting HDTV

Ok, i've searched the internet high and low.. found alot of similar problems, but nothing quite exactly like mine.

A few weeks ago, I bought an HDMI cable from a website. It arrived, I hooked it up (via DVI > HDMI adapter) to my GeForce 9800 GT, and connected the other end to my 42" RCA HDTV. It worked great, was playin games and everything.. next day, fired it all up... no go. The "NVidia Control Panel" no longer detected that the RCA TV was plugged in, and as a result, my computer monitor was the only display detected. I ended up getting a replacement cable, and that didn't work either, so it cant be the cable (not likely, unless they just happened to send me 2 duds in a row).. The TV is brand new, as is the video card and the DVI > HDMI adapter. I've tried it on all 3 HDMI ports on my TV - no good.

Now, one thing worth mentioning.. while i have the NVidia control panel open.. as i plug in and unplug the HDMI cable from the tv (or vid card), the Nvidia Control panel window flickers, as though it is detecting something.. but still, the TV is not shown in the dropdown menu.

I've tried the "click this if your display is not listed" thing, that didnt work. Tried "Forcing" it to detect on boot up, as per the other button, no use there either.

Anyone have anything like this happen? Anyone have ANY idea what's going on?

Very frustrated here. I appreciate any help,
Thanks in advance

-D