Ive had this dell for 4 years. I have had to buy 3 power cords and now I am using a 2 dollar chinese made one. IT sucks because it does not provide a constant source of energy to my computer. This is not the problem.
There are two settings: 1:when the computer is on the power cord energy it provides a greater light 2:when it is not the light goes to a dim mode.
ISSUE:when my computer senses the literally "every second difference" because the charger lacks the constant output. my computer switches from bright mode to dim mode, and anywhere from 30 seconds to 5 minutes the screen will turn almost all black.
You can still see what was going on but very very slightly and so much you can not see the mouse on the screen.
I can hibernate and come back to it again and hopes it lasts longer.
Is there a setting to make the screen brightness for the two different settings i said the same?
Where would I find it for windows xp on a laptop?
I'm not sure if the PSU is the entire problem. Your use of this cheap one could have damaged the unit. Does the screen still display this activity on battery only?
Anyway, it sounds like your backlight is dying. You'll need to replace your LCD and possibly the inverter to get it working again. Combine that with my recommended replacement of your PSU, you've got a pretty costly repair ahead, $400-550. If that's the case, it's time to get a new notebook.
You can change the brightness settings under power settings in the Control Panel.