On a fresh install (including reformatting the drive) of XP Pro with Service Pack 2 on an older Dell laptop, everything was running cool. Windows apparently found all of the standard drivers for all of my hardware, which is a first. I adjusted my video to the highest resolution, installed a wireless PCMCIA card and associated drivers and rebooted.
Everything was still smooth, POST ran through without a hitch, windows splash screen came up then it went blank, but I could hear through the speaker that normal processes were running but no video.
I booted in VGA mode, downloaded and installed the factory drivers from Dell for EVERYTHING, not just video. I rebooted on a normal startup...same issue.
So, ok, obviously this isn't a hardware issue as I can can see everything (even adjust the resolution to the highest settings) in VGA mode. The drivers were updated, so that leaves the BIOS and the OS.
I flashed the BIOS and rebooted...same.
I made the recommended changes to the BIOS as suggested on this forum...same.
That leaves the operating system.
I dug in deep in the devices (showed hidden hardware) and found that there were two monitors listed in addition to an AIM 4 video adapter to run a flat panel monitor. I have no idea where this came from, but I began the task of trial and error disabling and rebooting.
I disabled the AIM 4, and the flat panel monitor, leaving only the "default monitor" enabled. I rebooted and it worked....however....the resolution wouldn't go any higher than 640x480 in 16-bit...nasty.
So, now we know the problem. WINDOWS THINKS THERE IS AN EXTERNAL DISPLAY PLUGGED IN. When there is one present, all operations continue, but the video feed goes to the external display while the primary display is in sleep.
The final fix:
Before I dug into changing and hacking up drivers and customizing windows to do the right thing, I decided to let it do ALL of it's updates just in case it reverted any of my changes back to default and I would have to do them again.
I booted up in VGA mode...adjusted the video to hi-res (mostly so I could see everything), and let it go crazy for the next four (4) hours downloading, installing and rebooting. The problem was still there all the way up to the last update...Service Pack 3.
Get this...SP3 fixed the problem. I know, I was like "no way", but seriously after the reboot following the SP3 upgrade my video popped right up at the last-saved hi res setting, go figure.