press the Fn arrow up key to brighten the display
press the Fn arrow down key to darken the display.
When on Battery, sometimes the display will be dimmer. This can be manually adjusted be using the above commands.
I bought my dell inspiron 630 M laptop in Sept. 2005 since then the hard drive crashed and was replaced by the company , it becomes very slow now and the screen is not bright enough to see the matter on it.
I spoke to dell service center in INDIA and they insist me to get my screen changed whereas they never bothered to investigate the problem.I myself investigated and found the high voltage going to screen is not present thus screen is not bright , but LCD sreen is working( can see fade information on it).
Any information on this will be appreciated.