how do I fix tv to work as monitor?

Hi,
I have got one of these Mogen ML-1906TN 19" LCD tv and can't get it to work with my Dell PC.
when pc is on with a normal monitor i can disconnect the lead and connect to tv and it works but when i switch on the pc while is connected to tv it doesn't recognise the tv at all. any suggestions or ideas how to get the driver for this tv????

thank you