I'm not sure I can help directly, however for anyone to be able to help, please tell us:
1) What make/model and age of the television.
2) What sort of video connection goes to the TV (i.e. is it S-Video cable, VGA cable, etc..)
3) What video driver you use?
To see this, please provide us the "VGA Controller" section from the output of the below command:
4) What sort of Television encoding you use in your locale/region of the world (Is it NTSC, PAL, etc?)
5) See if your OS has a file called /etc/X11/xorg.conf
and if it does, please post its contents for us.
PS - Welcome to LQ!