Boot SAFE MODE and tell what happens. Sadly, the lamp failure is common and will cost more to fix than you suspect.
I have just turned on my pc (Toshiba Satellite Nothebook with Windows ME) - and the light has gone. It is functioning well enough in the introductionary fase, but disappears as soon as my desktop shows. The light has not completely disappeared, but I need a very bright lamp to see the weak desktop. WHAT HAS HAPPENED?! Have just run a virus check with no luck... HELP!!!