Dell Inspiron N5110 Display Flickering - What might be the problem?

Hi guys,

My Laptop is Dell Inspiron N5110 15R with Nvidia Graphics Card. 

I have now installed Windows 8. For the past one week, my laptop display is flickering. 

First, I thought that it might be some driver issues and formatted and reinstalled the OS. Even then, the flickering doesn't stop. 

The flickering doesn't come at the time of booting. It starts flickering only after the Lock screen comes. And then it continues forever. 

My system is out of warranty. Can you guys help me to resolve this issue.?

Thanks in advance. 

Regards,

Agathiyan.