I have a Dell 4700. I purchased a Radeon X1550 PCI-e video card to hook up my Samsung LN46B750 TV as a second monitor. I connected this via the DVI-I port with a DVI-D to HDMI cord. I have confirmed all setting are correct. The HDMI ports on the TV work. The DVI-D to HDMI cord works. The VGA connection to my desktop monitor works via the VGA port on the Radeon video card. I have researched everything I can on line, and I am stumped! Does anyone have a clue what the problem could be?