I've had the same kind of issue :
last week, after 2 years of running Vista home premium on my laptop HP pavillon DV9294ea (graphic card = Nvidia GeForce 7600 GO), with auto update on, I've first experienced 2 black screens for 2 seconds and then a windows message telling me that the graphic
driver nvlddmkm was not reponding and that windows handled the issue. It has hapened a third time causing a complete freeze and a black screen. Even during the boot sequence, I no longer had the HP logo, couldn't see the screen asking for safe mode booting
nor the Microsoft progresbar when loading.
Then, I've performed a deep scan of my computer for viruses => nothing found (NOD32). I've updated the bios to the latest version available => nothing changed except a need to reconfigure the wifi parameters. I've loaded the oldest graphic driver available
on my computer, the one of windows update, the one of HP and the one of Nvidia => none of them could allow a a full start of windows, either stoping with a blue screen before password entering or with a freeze 2 seconds after password entering.
Sometimes, the screen of the laptop is working, sometimes, only the external screen is working (this one is allways working).
The only way to to start is either safe mode (allways works on the external screen) or normal mode with standard VGA drivers. In this configuration, I've run the laptop for 2 days without any failure, just the sad looking 640*480 screen in 16 colors.
What are my conclusions :
I have difficulties to believe that my graphic card hardware is the issue as the computer is able to run perfectly during 2 days with a generic VGA driver and as the external screen is always working when the laptop screen sometimes yes, sometimes no. At least
one part of my card still works and this can be prooven.
Secondly, I've read many answers telling that because something wrong could be seen before windows starting was meaning that the issue was not linked with windows. I disagree with that. Why? Because even the vista progressbar uses obviously more than 16 colors
so this means that when it apears, some kind of drivers are allready loaded as this is not a VGA display that could be displayed without any driver. Another reason for this is that for the 2 years of running the laptop, I've never seen in it's display the
memory count which I can see on the external display : this prooves that there is some kind of intelligence (capabableity to hide some information) even when at the bios level.
Unfortunately, HP BIOS has been locked so there is no way to enter it and try to disable some functionnality or have a look to the GPU parameters. It's also not possible to try another graphic card as it is on board. The other thing is that this issue is too
common and too diverse to be a graphic card failure each time. In my case, I use the laptop only for internet, word and excel so nothing that could overload the graphic card too. My understanding is that from one way or another, some low level parameters have
been corrupted but windows does not help a lot to explian why it crashed.
Isn't it possible to get a nvlddmkm.sys file with various modes enabled and disabled to see which one is causing the issue as in my case, it is allready obvious that the VGA part is working correctly? From my point of view, Microsoft should provide possibilities
to enable and disable some features it uses on the graphic cards to help users determine what precisely is wrong. Just asking to use the newest drivers or to buy a new graphic card is not a fair option as at the end, this is a windows crash (blue screen) when
windows is at least capable to display that screen!