MBP screen starting to go dim

I bought my MBP in July of 2009, and it was ok so far today, but about a minute ago the display screen is starting to go dim, then immediately resumes its normal brightness. I've been putting my MBP to sleep when not in use by closing the lid but a few weeks ago my mac -savvy nephew installed a program whereby the MBP fixes itself and it's set to shut down at 4:30 AM on Sundays.

Why is my MBP display starting to go dim - its not burning out is it?

Do you have set screen brightness set to low and is the ambient light function checked
in display under system preferences? Also look at the energy saver preferences under
battery and see if automactically dim screen when on battery is checked.

Thanks - but this did not happen again afterwards. Screen is back to normal, no more dimming.