Video card Issue

Ok my friends computer is having some kind of issue with there video card, the card is an integrated model and they are not too sure what kind of card it is.  Anyway the issue is that the screen is just black plan black, no icons, noting.  They can however enter safe mode with icons and what not and they tried  changing the resolution in safe mode but that had on effect. Ok now this is how they said it happened and when it appeared.  It happened when they first the hooked up the computer to there new HD LCD TV and it worked out just fine (as they said) they went off to get a drink of watter or something  and came back and saw that the dog was sitting on the keyboard and then also noticed that the screen had gone black (comptley black).  soo any ideas of what happened? and how they could fix this issue? 

 

I think there OS is XP Sp 2 or 3