Reboot into safe mode (By pressing the F8 key when you start your computer) and see if you get the windows screen. If it is black in safe mode then means your windows is corrupted. If you can see the screen that means windows is ok. Run msconfig under safe mode then reboot and see if everything works.
There are many possible causes of the black screen of death in an HP Compaq NC6400. One likely cause of this issue would include a failed display driver.
On another note, there is probably an issue with the disk you are using or your X-Box system.
If your laptop has a black screen but the cursors still there and ctrl plus alt plus dlt works there may be a few issues. This could be a screen issue and bad LCD, loose or disconnected cable, or the backlight can be malfunctioning.
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Could be a problem with the circuitry connecting to the monitor. Take it to the nearest computerplace and they can diagnose the problem. A few common problems.... Defective screen cable or loose connectoin, bad inverter, or CCFL backlight on laptop models per 2010. Cable issues produce a black screen while an inverter usually produces a faint image. Also a bad graphics card is a possibility.
nothing
Nothing, unless you have a issue or illness.
Screen does not shake when you are using Gmail. It could be a monitor issue if you're on PC. Gmail has no feature like shaking screen.
There could be many reasons why your screen flickers black. It depends on which screen, your TV, computer or phone. Your TV may flicker black because the picture is going bad. It could also be a a signal issue from your cable or satellite company. If it is your phone, there may be water damage, or some other damage. If it is your computer it can be the same thing as the TV. The picture may be bad, or the power supply isn't connected properly. You can call your cable or phone comapnies, or the manufacturer for your product to get help.
Nothing, unless you have a issue or illness.
Nothing needs to be done unless you have a medical issue.
nothing