The purpose of this article is to provide Vista computer users with the method to install a secondary monitor, as some Vista installations have a bug that prevents dual monitor setup.
Problem: Assuming that your computer has a video board installed on the motherboard that is in addtion to also having the standard video plug, some Vista installations have a bug that prevents a secondary monitor from being utilized.
1) Open Device Manager and for each of the display adapters right click,
2) select “driver update driver software”
3) Then select “browse computer”,
4) “let me pick from a list”,
5) uncheck “compatible hardware”,
6) then select the non certified microsoft versions and without the XDDM
or WDDM designations.
7) close and
8) repeat the above for the secondary display adaptor.
9) then reboot.
10) after logging into Vista right click on desktop, select “personalize”,
then “display settings” to fine tune both monitors for extended desktop
Conclusion: For whatever reason, Vista did not support dual monitors like the previous XP operating system. Perhaps, it had to do something with the new / fancy Vista Aero Desktop. However, after executing the steps above, the Aero Desktop will now play on both monitors.
It is unclear if Microsoft provided a fix or update to correct the dysfunction..
However, the methodology above was provided to a Microsoft Engineer, who responded with interest in 2009. For further reading: http://tinyurl.com/njdo9q