I have a Samsung TV, model LN40A450. I'm trying to hook it up to my PC via HDMI cable. video card is Gigabyte GTS 250. Here's the problem. Image will show up without a problem on duplicate display mode (Monitor+tv), and also on extended dual display. But when i try to select Single display (for TV only), the tv will become blank and show mode not supported. When i bought this tv it was advertised as a 1080i. ps3 and xbox shows it supports 1080p resolution, but the online manual specifies this tv is only 720p. The in-box manual is a generic one for multiple models of tv and the resolution is not specified. But that doesnt matter because even if i set up the resolution to 1024*768 (which the manual states my tv supports), i will still get the mode not supported message. The problem should not be there anyways since it will display 1920*1080 in duplicate display mode. it is not an issue of frequency either since the default configuration is 60hz. So i'm out of options here. can anyone think of what the problem might be? i just bought a cheapo 3m hdmi cable today but it shouldnt be the problem either..?