I've read Tom's Hardware for years, but this is the first time I've had to post a problem.
When I boot up the computer, it loads normally up to the point that the Windows splash screen is supposed to disappear and take me to my desktop. But, it's just a black screen!
No icons, no mouse cursor, just blackness.
I can't bring up task manager or make the system respond in any way.
I've run quite a few bootable diagnostics, but nothing I've been able to find indicates any problems.
I've tried to boot in VGA mode, Safe mode, nothing works.
This problem began a few weeks ago. WoW is the main game that I play, and I began to notice a slowdown or "stuttering" in my gameplay, followed shortly after by the game locking up, accompanied by a loud buzzing noise coming from the speakers.
So it loads upto the the point the OS switches from the loading screen resolution to the desktop resolution.
Normally I would say the refresh / resolution has been set too high in the graphics set up and suggest booting to safe mode to fix this or that a graphics card driver update has gone wrong, but
You can't get safe mode to work
The VGA mode won't use the nVidia drivers and you can't get that to work either...
Still, this is the point the graphics driver takes over, so I would lean towards a graphics card issue. Can you try a different card, or does your system have on-board graphics you could test? The card typically draws more power at this point so it could also be a PSU issue as PsychoSaysDie suggests but I would check the card first..