What causes a blackscreen?

  • Thread starter Thread starter Bob Day
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Bob Day

If a computer has been running along normally for a
while (not during POST), what can cause it to
blackscreen, as opposed to bluescreen? I know that,
for example, if XP tries to page while executing a DPC
routine, it'll bluescreen. But what are the internal error
conditions that can cause a computer to blackscreen?

-- Bob Day
 
Bob Day said:
If a computer has been running along normally for a
while (not during POST), what can cause it to
blackscreen, as opposed to bluescreen? I know that,
for example, if XP tries to page while executing a DPC
routine, it'll bluescreen. But what are the internal error
conditions that can cause a computer to blackscreen?

-- Bob Day
Click to expand...

Broadly speaking...

1) Power scheme that programs the monitor to turn off. (See Control
Panel/Power options)
2) Screen saver that blanks the screen.
3) A flakey graphics card.
4) CMOS settings that are unstable for the given hardware installed.
5) A flakey Power Supply Unit.
 
Bob Day said:
Thanks. And thanks for your response to my "Three beeps - not
during POST" post -- I tried your first suggestion and reseated
everything yesterday. So far so good -- we'll see what happens.

The question I was trying to ask, although maybe not clearly, is
this: If a computer blackscreens as a result of 3, 4, or 5 above,
what happens in the circuitry or logic of the computer to cause
that? -- A bus error maybe? Going into nonexistent memory?
An illegal instruction? Why does the computer choose to
blackscreen rather than bluescreen?

-- Bob Day
Click to expand...

I hope things hold for you. :o)

I can't believe I forgot to mention drivers..... it is remotely possible
that a bad/corrupt driver could cause a black screen.
It may also be that a BIOS firmware update is needed - or that an incorrect
one was loaded. Possibly a motherboard driver. But that's unlikely if the
system boots at all. I think the original list covers the vast majority of
causes of black screen....

I think a Blue Screen of Death (BSOD) represents an instance where the OS
was able to identify what caused the error (or at least, if not the true
cause, the first critical device/service that could not function *due* to
the real cause) (For example, a driver may not work right if the hardware is
flakey... but it may be the driver that comes up being reported as the
"cause" of a BSOD)... I think a black screen represents a case when the OS
was not able to handle the error prior to total lockdown. (Again... I
*think* this is the case... I haven't personally seen anything to contradict
this hypothesis... but others may well know.)

If the error is sufficient to cause the system to die, but not sufficient
enough to prevent the OS from - in a kind of dramatic last gasp - point a
finger at the accused, you get a BSOD.

Have a look at your system error logs (Available via System Information,
subcategory Software Environment, then Windows Error Reporting) to see if
there are any clues. Match the time stamp of any errors reported with the
time you receive the black screen...

Regards
 
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