Macbook Screen Problem (with picture)

this is a macbook bought in december 2008. with lots of use, the screen lost it's...firmness? and is now wobbly in place. suddenly these lines appeared and they won't go away. sometimes, when it's tilted a certain way, it stops for a moment only to start up again. it's smack dab in the middle of my screen and a liiiitle frustrating. any help is appreciated, thanks

Most likely a cable is being pinched or crimped - possibly the video cable. There are numerous cables which run up from the logic board to the display and snake up between the hinge area on the MacBook. Repeated opening and closing of the lid will sometimes cause this. You'll probably need to have an Apple service technician repair it for you. Get an estimate first.