I have a Sansui 19" lcd tv that I want to connect to my computer as a second monitor. I have it connected to the dvi port on my PC with a vga to dvi adaptor. While the computer is booting I get identical video on both my lcd monitor and the Sansui TV, but once Windows loads the TV's video goes away and is replaced by "No Signal." What do I have to do to get the TV to participate in dual or extended mode? I have a GeForce 6200 video card with VGA and DVI ports, running on a windows XP Pro machine. Each monitor works well separately on either port, but the TV will not work with the primary monitor.