Secondary screen problem

[JohnFL1983]

Hello, I have a MacPro 3.1 and I have a weird problem. When I'm using MacOS my second monitor, a Samsung TV, is working great. When I'm on Windows XP (unfortunately I'm using some programs for machines that are working only in XP) my secondary monitor is not working. But if I connect a second 17-inch display, it is working just fine.
I have updated my system and still the same.
Is there anything I can do? I need it for presentations.

Thanks in advance.

ps: I wish I didn't have to use windows!!!!

 

[bax2003]

Tell us more about how is LCD connected to your mac. I presume you have Radeon 2600 XT or GF 8800 GT. So DVI to HDMI cable to LCD ?

 

[JohnFL1983]

I have the Radeon 2600XT, as you said, and yes it is connected with DVI to HDMI. I cannot connect it with DVI to DVI because there is not a DVI port to my LCD.
This LCD is working fine with an older computer that I have with windows XP.