What happened to my monitor?

For the past few months I have been using two monitors. I have a Dell Inspiron 5150 and I also hooked my old CRT monitor to the laptop. Everything has been working fine until recently when my laptop screen started to dim - and now you can barely see what is showing up on the screen. The only way you see anything is when I shine my lamp on it. The other monitor still is working, but I was just wondering what happened to my monitor and if and how it can be fixed. Thanks

[FouTight]

Sounds like you lost your backlights. Is it a new computer? may still be under warranty. Those are typically expensive.