The notebook computer is an HP Pavilion Entertainment PC, which is a little more than 1 year old.
The original chief complaint was that the computer was not working right.
I ran a diagnostic on the hard drive, which was recently replaced, and found that it was starting to fail (seek errors).
A replacement high performance 60GB SSD (OCZ Vertex Series) was installed, formatted slow (as opposed to doing a quick format), the OS was installed, and the machine rebooted fine.
The first wave of OS updates that were applied were large and many and time consuming to apply, so I left the machine alone while it did it's updating thing.
When I returned to the machine several hours later, I could see that it was on, but the screen was dark. Pressing a Shift key or dragging on the touch pad had no effect on reawakening the machine.
I pressed and held the power button for 7 seconds to force a power off, but the machine went to sleep (may have hibernated, not sure because this was several days ago, but the "shutdown" was faster than a hibernate normally completes) sometime before then. Pressing the power button again resumed the machine. I was able to eventually crash the machine, and booted successfully into Safe Mode.
I changed power setting for the power button to be "turn off", so I didn't have to worry about whether seizing control would be effective or not.
With a lack of symptoms, my first suspicion was to point the bloody finger of accusation at the display driver, because the screen flashed during startup (granted, this is barely hearsay evidence and not smoking gun conclusive evidence, but this seemed as reasonable a starting point as any). I went to the Device Manager, checked the driver, and found that there was no previous driver to roll back to. I uninstalled the display device, manually launched device discovery, rebooted. I tested many times, shutting down and rebooting the machine, and this seemed to solve the problem. So I shut the machine down and left it alone. The power adapter has remained connected continuously, and it has remained plugged in to a UPS which has consistently delivered power through no power outages.
Now, several days later, I went to turn on the machine, and the same problems that was previously believed to be solved is now presenting itself again.
First, from the time I turned on the machine today to the time I remember seeing the bios splash screen first displayed, the elapsed time was about a minute. (much longer than bios initialization on this machine normally takes)
Second, the OS eventually started to boot automatically, the 4 little colored things that are a visual signature of Windows 7 came together and did their little dance, the screen flashed very briefly, and I heard the windows startup sound, but I noticed that the screen remained at a static unanimated "Starting Windows" screen.
Third, the hard drive activity light was still blinking for 5-10 seconds, then settled down to be off, suggesting to me that the OS was still in the process of initializing itself.
Fourth, I pressed the power button to shut down the machine, and could hear the "shutting down windows" sound, but the display remained at the static "Starting Windows" screen. The machine did not turn off.
Fifth, after about 10 minutes (or so) of no interaction, the display went black, but the status lights on the notebook remain on. The status lights are: the power button is backlit as white, the speaker muted is amber, the horizontal volume slider is white, the blue wifi indicator light, the numlock indicator, the touchpad indicator is white, and the power on indicator on the left front corner is white. These indicators are all normally on while the machine is powered on.
So right now, the machine is on, but the display is off, but the indicator lights are on. There is no visual sign than an OS is running (no mouse pointer, cannot toggle the capslock/numlock indicator lights), and the machine is unresponsive to anything other than pressing and holding the power button to force a power off. (note: about 20 mins after the screen went black but all the indicator lights remain on, the cpu fan has begun to turn much faster and is now audible - I estimate the fan was turning at half speed, feeling the bottom of the notebook most areas were cold with a very few areas warm but not hot.)
I pressed and held the power button, forcing a power off to occur, then pressed the power button again to begin the boot process. The bios initialization completed promptly (about 1-2 seconds), and I booted into safe mode with networking. The OS was up and operational, automatically displaying the "what is safe mode" explanation screen.
I clicked on "shutdown" on the start menu, and the machine silently turned off within a few seconds. The screen is now black, and all indicator lights are off.
I pressed the power button to turn on the machine, saw the "Starting Windows" screen, heard the multi tone windows startup sound, but the "Starting Windows" remains displayed as a static image on the screen.
What I seek is guidance, on what to check next and what to do to learn more about what might be going on here, in the hope of solving this problem.
Thank you in advance for your help.