Hi shahzeab,
Go to this location in your browser:
http://www8.hp.com/uk/en/drivers.html
Then click on the "Find now" button as indicated in the screenshot I've supplied
Install any plugins/software you're prompted to install.
You could be asked to switch off any pop up blockers enabled in your browser, which you will need to do for the HP "Detect my product" plugin/software to work.
Heres how to switch off pop up blocking in Internet Explorer:
http://support.microsoft.com/kb/909604/en-gb
The plugin should then detect which exact model of laptop you have
At which point a webpage should appear indicating which model of laptop you have. It will look like this:
Click on "Software and Driver Downloads" link next to the pic that displays a laptop:
On the following page click on the link that displays the OS currently installed on your laptop
Lastly click on the "Driver - Graphics" link and you'll see the driver for your "AMD Raedon 6480" listed - download that driver and install.
At this point I would also install any other drivers you've detected that are out of date (along with your AMD Raedon 6480 video card driver) and restart the OS
Please get back to me if this doesn't fix the problem.
Martin