using TV with laptop

[accessys at smart.net]

Got a new HD TV, and wanted to hook the laptop to if for occasional use, but 
the sound works buts not the video.   System 76 laptop with ubuntu 8.10 running 
and gnome.

new HD TV fairly generic with lots and lots of plugs on the back.  use the VGA 
cable from the video out slot on the laptop to the VGA slot on the tv and have 
all the tv settings correct.  but still no video,  like I said sound is fine.

before I run out and buy a HDMI cable is there maybe something I'm overlooking.

Bob