no signal from pc to hdtv

Yeah I looked and its
lg 32LC51

eng.pdf download - 2shared
here is the manual

It worked when I had the pc set to 1680x1050 too.

I dunno. It worked fine before :|. I'll send it to service as I got no idea what else to do.

Have you checked the TV's HDMI port for dust? It accumulates pretty quick when the ports are left empty for a period of time, so I'd do that first and if you see it in there, blow it out with a can of air or a compressor if you have one (be sure to not let any liquid spit out first, it's happened to me before so just test it). You'd be amazed what just a tiny little fleck can do. Think back to those Nintendo cartridge games, eh?

However, since you say nothing else has changed other than the GPU driver, that's probably it right there. See if you can't roll that driver back to the previous version in Device Manager or else restore your system with Windows Restore to the point BEFORE your GPU driver was changed. Failing that, I don't know.

I use an external monitor on my mobile computer and it recognizes the connection within 5 seconds (albeit I have to press fn+F5 for it to switch over the first time, then mess with the CCC settings).

Also another thing you could explore for possible physical problems with the TV or graphics card, is to try a DVI/VGA connection if your GPU/TV supports either of those.

It's weird that the pc does see the connection to the tv. In the nvidia control panel, it sees hdcp connection with the LG and in the "set up digital audio" it also sees the tv in the hdmi bar there.
I don't remember what driver I had last time it worked.

I notice there are sparks ( a couple of sparks around the hdmi port and I hear nothing) when I connect the cable to the pc. What does this mean? I suppose it's bad news