DVI to VGA connection not working

[Andrasitc]

Hi everyone, I just got my HTPC and connected to my LG LH7000 lcd full hd tv, but I have some problems. When I use VGA to VGA cable I get the picture on tv but not in the full resolution1920x1080. When I set this resolution, I have to "pan" the desktop on tv. Since the motherboard has the DVI output, I tried to use the DVI to VGA cable, but my tv says "no signal". Mobo is biostar TA790GXB3 with integrated ATI HD Radeon 3300. How can I make the DVI output working?
I must mention that before I tried the same tv with the same cable but on other computer with ATI HD 3300 that is not integrated on the mobo and it worked perfectly.
I use Windows XP SP3. Also tried with Win 7 64 bit and Win 7 x86, but always was the same problem - DVI connection not working

 

[fimbles]

Its strange that you have to pan the desktop at that resolution as a standard vga to vga cable should be able to display that resolution fine, and as far as i can google, so can your tv.

Its sounds to me like maybe a tv setting. Does the aspect ratio set itself to something funny like superwide or something?

 

[Andrasitc]

aspect ratio is set to 16:9. I know it should be "just scan", but that option is not available