Windows 7 Black Screen when booting up

Hello there,
I’m using Dell Inspiron N5050 laptop.
Configuration: Intel core i5 2450M,6 GB ram,1000GB of hdd & intel HD 3000 graphics. I’m using windows 7 Home Premium 64bit on it. It’s a pretty good laptop.
But, the problem occurs at the start up.When I turn it ON, dell logo comes up & the screen goes black. Then, I turn the laptop again.After doing this same job for several times,the start screen comes.
Now, my question to you guys is how can I solve this problem permanently?