yep... this same thing happened to me

i had two PowerBook G3s - - - - I had A PowerBook G3 Wallstreet 233MHz and my father dropped it a few times, the battery stopped working, the CD-ROM player stopped working, so basically I just had the screen, harddrive, keyboard, and trackpad and most of the stuff inside still intact. I was using this laptop as a desktop basically for ClarisWorks(remember the good 'ol days) and dial up interent

And then one day, the screen went into tons of little lines, all diffcerent colors, half the screen was basically dead. It looked like a TV without CABLE/SAT(all messy, no picture)
so then I tried hooking that up to an extrenal monitor but the thing was dying, and so my dad one night took it out of my room, and thru it in the trash
Then when I was older, I was thinking, remembering how much I loved that PowerBook, and thought, damn, i'm just ganna get another one off of eBay, and so I did. I got a 250MHz WallStreet, 320RAM, CD-ROM, and got a new battery for it. It worked pretty damn good........... until the monitor started to turn blue for a few seconds on and off

I was more experienced in the technical world, knowing how to take computers apart, knowing what i was doing. I took the monitor off and hooked it up to an old Compaq monitor. Worked great for a few weeks. Then everything started to run verrrry very very slow. One of the RAM sockets died on the mobo, and the hard drive died
I was very upset

and then I sold it on ebay for parts.
Now I'm saving up for a PowerBook G4 12" .---- hopefully these PBs are more sturdy than older generations
Good luck with you PowerBook screen, those PBs are great, fix it, you'll be glad you did