Video not functioning

[The Doctor]

Got this from a customer using an HP laptop running Vista.

Suddenly the video in regular stops working but all right in Safe Mode.

How does one debug this?

 

[Chuck]

Normally, you would think that the video drivers or another piece of
software is the culprit. While likely, you should also consider that running
in safe mode may not stress the laptop video as much as a graphics intense
application in normal mode. Another occasional gotcha with laptops can occur
when the laptop's video system can support resolutions greater than the
laptop's screen resolution. It's possible for a game to default to one of
these higher resolutions, and switch to an external display output, or just
display a blank screen on the laptop. How to get out of this sort of thing
is more or less model dependent, and may be simpler if an external display
is connected. Some laptops have BIOS options as well as system unique in
windows video setting options. It's also possible that your laptop is one
that happens to have a defective video chipset or a bad cooling fan. Some
HP laptops using an Nvidia video chipset had similar problems, due to a bad
run of video chips two or so years ago.