[ddouglass]

You may be encountering two different problems. As Roy said there are two types of Svideo cables and plugs. If you aren't using the correct cable for those then you will have color problems.
To check your show set up try using the vga to converter to yellow (RCA) out to the big TV. If it is still Black and White then the problem is not in the TV. If it is in color then the problem is the older TV you are using.
If you have a desktop computer at home borrow the monitor. Use the VGA cable you use for show setup and hook it up directly to the laptop. If this works and shows color, then you have eliminated the laptop and the VGA cable. For that point on it is either the converter or the RCA cable.