When you open your display properties, do you see it as a connected device?
Often times the output ports will engage on startup, and then disengage as Windows loads the current drivers.
Here are my suggestions:
1. Update your BIOS
2. Update your video card drivers
3. Check to see if it detects it.
4. Toggle your video out (often Fn+F7/6/8/etc.
If that doesn't work, you might try calling tech support to see what resolutions you can come up with.
Keep me posted.
--HDTech
TV Model: LNT4061FX/XAA
Version: CN06
I currently am running my newly built PC to my Samsung TV. The problem I am having is it works VERY inconsistently. Sometimes, it displays the PC BIOS, to log in, and actual logging in. Sometimes it display the PC BIOS, to actually booting into Vista, but then it will drop the signal and display "low or weak" signal. Most of the time, it will not display anything at all except "low or weak" signal. The frustrating thing about this is it is intermittent.
I verified it was not in shop mode, per this forum. The "just scan" and "wide fit" options are greyed out. Which I understand needs to meet a signal req to be available as an option. Having said that the video card being used is an EVGA GTX260 with DVI to HDMI adaptor, using a 1.3 HDMI cable that was being used for my cable tv (was working fine).
I am pretty much at wit's end trying to figure this out, if I could "force" it into "just scan" mode I am sure it would work. The OS I am using is Vista 64 Premium.
Thanks in advance for your help

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic