This may not be the only solution, but I found it works.
Create a privileged task to run a batch file at startup with lines similar to the following:
devcon disable "PCI\VEN_8086&DEV_010A&SUBSYS_04981028"
devcon enable "PCI\VEN_8086&DEV_010A&SUBSYS_04981028"
The string is specific to a particular graphics board/chipset; you would need to find the string that works for your system using 'devcon findall *'.
The devcon utility is part of the Windows WDK. You need to make sure you use the correct one for your architecture (32/64 bit), and if you are using XP, good luck finding a copy!
The symptom this solutions addresses is for a Dell with HD Graphics 2500. There are ports for HDMI and VGA. The HDMI port works only immediately after install. Once you reboot, the HDMI port does not activate and the control software won't let you do anything with it. I tried multiple drivers from Dell and Intel.
I followed a suggestion from this post: /thread/28044 https://communities.intel.com/thread/28044 that disabling and re-enabling the driver inside device manager was a work-around then generalized it to run at startup.
