Ok, so here's the deal. I just get back from a trip to Switzerland - where I held a presentation using my laptop and thus did fiddle with some settings - and I plug my external monitor on my laptop, fiddle the settings back, and it won't work.
I have an nvidia graphics card, so I use nvidia-settings to do this, which has worked fine so far. So I'm trying to get it to work in a TwinView clone setting, but the monitor in question jabbers on about checking the signal cable.
Now strictly speaking that might be the problem, because I fail to get this to work even in Vista and on my TV, but the display is detected, so there is something alive in there somewhere. I also can't get myself to believe that the problem is the monitor... it has served me well for a year and I didn't do anything to it.
Anyway, from what I gather nvidia-settings works by updating xorg.conf, which I've not learned to decode, but someone out there might be able to make heads or tails of this and tell me if it makes sense (attachment).
From there, I'm out of ideas.
Thanks,
BB
Edit: Should say this is on Ubuntu 8.10.
Edit: Tried a different cable and monitor, and it didn't work. I'm beginning to suspect that the VGA slot in my laptop is damaged, because the VGA cable I used in Switzerland (see above) failed to display green, maybe there was a short circuit or something, I dunno... Maybe I should try the HDMI port.
Edit again: Tried that too, same crap. Now I'm officially out of ideas.
Here is a copy of the xorg.conf which I use when I want to use a Twinview setup. It is for an nVidia 9500GT card with dual HP w1907 monitors. You will obviously have to edit Files and Monitors sections at a minimum.