Laptop Display problems

I would like to be able to hook my vista laptop up to an external display and shut the screen to use only the external display with my wireless keyboard and mouse. The problem is that whenever i hook it up to my LCD TV with an RGB cable its works fine until I shut the screen, when it says that the input format is not supported and i need to change my pc output settings. I have had it work with my laptop closed before and as far as I know no settings on my laptop have been changed since then, the laptop is set to run normally when the lid is closed, so I dont know what is wrong. Another issue, when i set it to only display on the external display it displays it on my computer screen, and not my lcd tv screen, and i cant figure out why that happens either. And lastly, is there any way to make it default to a specific resolution when I plug it in, because the resolution it defaults to now is bad.