Mac Book Pro screen weirdness

I'm have a strange screen problem on my 15" 2008 Mac Book Pro (last model before unibody.) About half the time I boot up the machine the lower portion of the screen has what looks like alternating light and dark rows of mini spotlights shooting up from the bottom of the screen. One inch swaths of the screen are more illuminated than others and the entire effect fades about 3/4 of the way up the screen. If I reboot (sometimes several times) it will go away and the screen will look normal again.

What's going on???

Avoid any Alcohol solution to clean screens. Long ago I cleaned my laptop with Isopropyl Alcohol and the Alcohol solution was absorved by the screen. My screen become clearear in some areas and, not sure if that is your issue, but looks like.

you have a lose connection where the ribbon meets the screen or motherboard/ Gcard. If you are comfortable enough to break down your lap top I suggest doing it yourself, otherwise, pay someone