Can I connect dual monitors through DVI and HDMI?

What is going on here? Connecting TV and PC with DVI-HDMI, no signal?

• Here's the story: My friend wanted to hook up his hdtv to his computer to use it as a monitor. His tv is capable of being used as such. I decided to help him because I have some cables he needs. I plugged a DVI-HDMI cable into the back of his pc, and into the back of the tv. However, windows xp(his computer is about 2 years old) doesn't detect the tv when i go to the nvidia control panel to set up the multiple monitors, and it also isn't there in the normal display properties area. However, in the nvidia control panel I can force detection of the tv and it'll say it found it. However, it just says "TV", without saying what kind or anything. Well, I set up the old monitor and the tv as dual monitors(and tried every other option as well) and the tv is still saying no signal, so its not detecting the computer I guess. I'm not sure why this is happening and I'd like any help ya'll have to offer! Thanks in advance! :) Btw, I know the cable works because I've tried in on a known good computer and tv in the past week and it worked perfectly. Also, I know the tv can be used because I tried using a VGA cable to connect the pc and tv and it worked perfectly. However, I'd really like to be able to use the DVI-HDMI cable. Extra detail: There is no function key so don't try to suggest using that and pressing one of the "F#" buttons. All of the drivers are up to date for his system as well. Please give any help and advice you may have! It feels like I've tried everything!

• Answer:

  Tv Model and Graphics card...?