Dual Monitor not working

Hi,
To simplify things, the name of the pc's are 'spectra1' and 'spectra3'. Spectra3 already has dual screen, and I'm trying to connect and 2nd screen for spectra1. I went to System Settings > Display > Dual head tab: on spectra1 and enabled the "use dual head" then clicked Configue...

From there I selected the model of my monitor, however I wasn't sure which monitor it was referring to, the main monitor (Monitor0) or the second monitor (Monitor1). What I did I just used whatever spectra3's model was and used that one (in this case Dell 1905FP (Analog).

Upon finishing this confirguration, a message appears stating that I need to log off and the X-server needs rebooting. When I log off the pc tries to log back in but the nvidia logo appears for a second and then a black screen. This continues a few times and then a message in dos appears stating that the X-server can not be started.

Please see quote1 for spectra3's xorg.conf and quote2 for spectra1's xorg.conf and quote3 for spectra 1's single screen xorg.conf. I see a couple of differences between both xorg.conf for the dual screens, but not sure which ones are actually causing the problem.

Any help would be appreciated.
Kind Regards
Russ

spectra3's xorg.conf (dual screen)

spectra1's xorg.conf (dual screen)

spectra1's xorg.conf (single screen)