[CentOS] How to display laptop screen on LCD TV?

Hi,

I am running CentOS 5.2 on Acer laptop, I try to display laptop screen
on a LCD TV via VGA cable. It was fine while PC was booting in text
mode, but as soon as I started X Window, the LCD TV has error
"Unsupported signal, adjust your PC out".

How can I adjust or may be regenerate an xorg.conf for the LCD TV
(Sony KDL-40V5500)?

Thank you.

Kind Regards,

Jupiter