I am trying to run a dual monitor setup, with a computer monitor and tv mix. I am using one video card with a s-video output. When my pc boots it shows everything up to the to the x screen when fedora starts to load. once the x screen hits the tv starts to this non stop vertical loop.I have tried to adjust the settings in the software but still once the x screen shows that loop starts.

What video card are u using.
ATI radeon, Nvidia Geforce,....
This info is needed to be able to help you.
First of all you are probably going to have to install the original driver of you're graphical card.
I don't know about the ATI card but it is possible to do it with the NVIDIA geforce cards but it's not that easy to configure.

I am using a Nvidia mx card.

go to /etc/X11 and open XF86Config or XF86Config-4 and look for the line
Section "Device"
in that section you should find a line
Driver "nv" (this means you're using the standard linux driver no 3d support)
or
Driver "nvidia" (this means you're using the NVIDIA driver)
you will probably need to install the driver
you can download it at
http://www.nvidia.com/object/linux_d..._1.0-6111.html
also download the readme.
it explains how to install it of search the internet for a HOWTO guide for you're distribution. For the installation of the driver you will need the kernel sources of the kernel you are using.
Once you got the driver up and running you can try to configure you're tv out.
It is explained in the README file of nvidia ( it's not that easy to understand)
i never got is completely working the way i wanted so somebody else will need to help you with that.