Help!! My Powerbook is starting to make me trouble..

I bought this Powerbook a couple of months ago used, but in very good condition. It never made me any troubles and it worked fine all the time. Just last week, my power adapter died and I had to get a new one. I ordered one and received it three days ago.
Anyway, my problem now is that since last night, when I turned my powerbook on, all of sudden some strange white lines appeared on the top that were lightly flashing. This would not go away. Instead, more lines appeared all over the screen. It drove me nuts because it wouldn't go away and I was afraid soon I was not able to see anything. After about two minutes though, the lines disappeared completly and everything was fine.
However, this morning the same thing happenend and I have no idea what it is and why does it show up and then disapear...this is very strange.
Is my screen dying? What should I do?
Thanks!!

I don't think it has something to do with your new power adapter. However I would suggest you to reset PRAM. You should follow the instructions here.

Thanks for your fast reply!! I tried the link and reset everything but nothing has changed. Now, the lines come up more often and this morning it was all over the screen..it was bad. Do you think I should bring it in into the apple store? Or is there anything else I could do?
Thank you!

I think it is the next best thing you could do. Go to the nearest Apple store and let them do a check.