I am using a tool from HP called hp Health Check that runs one time per week. Till now I didn’t get any recommendation that I didn’t know about but today that changed.

External Display Detection Issue

There is a known issue with Vista operating systems where external displays will not be detected or will display with the resolution incorrectly if the notebook is booted with the lid closed or if the lid is closed soon after boot.

Frequently Asked Questions (FAQ)

When turning on your notebook computer be sure to have the lid open. After logging in, you may then close the lid of your notebook computer.

In the Windows Vista operating system there is a new feature called Transient Multimon Manager (TMM). This feature takes care of the detection and handling of connected displays. When a notebook computer is booted with the lid closed, Transient Multimon Manager is disabled.

More information on this topic is available on the Microsoft website at http://support.microsoft.com/kb/941413.