Usually in this model of laptop we found intel graphics driver . so you need to install an Intel driver.
you can find this driver from Your official Intel website - http://www.intel.com/p/en_US/support/detect
But there are some model of this laptop uses nVidia Graphics driver also. so if you have an nvidia graphics driver then you need to go nvidia driver site and then you need to install it.
http://www.nvidia.com/Download/index.aspx?lang=en-us
If you don't know about brand name of your graphics then you need to run msinfo32 command on your computer then you will able to see there your graphics driver on your computer.