No signal from PC to TV

[Uhtred871]

Every time I click play on Rome 2 a little box appears with the other TW games I hae on steam. I click play on this screen, then my screen goes black and a box appears saying there is no video. This message would normally only appear when the screen is on but the PC is switched off/ HDMI cable is unplugged.When this blank screen appears there is still sound so I know the game is still playing. This happened on Napoleon Total War as well but the other Total War games work just fine.
I've installed it on a laptop and it will load no problem however the laptop is not powerful enough to play the game. However when I conect my laptop to either of my LCD flatscreen TV's the screens don't register that the laptop has been hooked up to them.
Can this game only be played through a monitor? If this is the case, why allow Empire, Shogun 2, Medieval 2 and Rome Total war to be played through a HDTV?
Just so you know that my computor is good enough to play Rome 2, it is an Alienware X51 i3 and I can play Shogun 2 total war on very high graphics settings. Currently playing Guild Wars 2 on ultra with no lagging or any other issues.
I do't know what is worse, possibly having to spend a few hundred quid on a decent sized monitor or that I took a week of work to really get stuck into a game that I can't play!

Sorry for rambling