I can't burn any CD's more!!?

It's quite probably a dirty laser lens. Buy a lens cleaner disc from any good music or computer store and follow the insructions. If this fails the drive may be dead. You can buy a CD/DVD burner now for under �40 (UK) and they are simple to fit. Just make sure the jumpers on the back are set the same as those on the existing drive. Only two cables to unplug and replace it's a 10 minute job. Hope this helps