I'm sorry to hear about this issue. Could you please provide for me the complete model codes for the TV and the laptop? Also, I assume you've tried more than one device hooked up to HDMI, such as a Blu-ray player: are those behaving fine as well? Also, is there a particular reason you're trying only the HDMI connection? Is VGA or DVI not an option?
I have a Samsung notebook and I'm trying to connect it to my Samsung TV (T200HD) when I connect the two via HDMI cable the laptop picks up an Internet connection (I don't understand how or why) but won't recognise the TV, the TV says no signal, I've tried in the HDMI port one & two and they both come up with the same message (the TV recognises which port the wire is in) when it's not connected the TV says check signal cable, I've tried FN & F4, it only shows the one screen & then doesn't respond!!