The CCFT tubes or supply fails. Look in the notebook forum and ikenfixit.com or notefix.com is a common place to ask "how much?"
As to the CDs, the next problem is that without such, they will only run this OS until they hit some bump in the road. Those CDs are worth about 100 to 400 bucks!
My neighbor has just given me her PC to look at. It's a Sony lap-top. Don't know what year but it's model #PCG88SL. It runs Win XP. It will start up and open up windows but the screen is so dark that I have to take a flashlight to see anything at all. She has no disks or anything with this PC at all. I can't find any levers which might brighten the screen. Can anyone help?