HP Compaq Presario F761US Notebook "sony bravia display blank" Questions

...Sony Bravia flat screen. Hi: Just plugging in the monitor to your VGA port on the laptop won't make it display. You have to toggle to the exteral display, or both. Usually you have to hold down your ...

...Sony bravia tv. When vga connected nothing happens at all on laptop but external monitor says " check cable" ( have tried another cable ). If connected in power off condition external works and Tv ...