I have a 5-plus year old Dell Inspiron 1525 and its screen becomes extremely dim usually within a few minutes after plugging in the adapter that came with it into the power outlet. When I shine light into the screen, it is a little better. The Fn and up button does not do anything. And yes, I've checked the settings to ensure maximum brightness.
When I unplug and the computer is on battery, the highest possible brightness with Fn and up button immediately generates a beeping like sound and the screen flickers. Hitting Fn then down lessens this sound but there is still some flickering. But it's okay when I hit Fn then the down button another time.
Can you somebody explain in very simple terms how to fix this (I do not understand computer lingo)? Also keep in mind that the laptop is barely worth $100, so I will not be spending money if it doesn't make sense.
Thanks in advance