My screen to my lap top wont come on...I really need help!?

I have a dell Inspiron.1721...When I click the power button the blue power light turns on but the screen stays off. How can I fix it to make it come on again? I tried letting the battery drain and the charging it to see if it would work but nothing. It all started when I was on the internet and all a sudden the screen just turned black. If anyone knows how to fix it or might know a way I would be very thankful!