With any laptop, the first place to look is the maker's web site.
Once there, you launch a search for your model and "driver".
You should get a page containing one or several downloads adequate for your computer. You are very probably interested in the video drivers.
Take the most recent available, probably in the video section.
Next, if you can't find updated drivers from the computer's maker, you need to know the brand of the video part. From the controll pannel, open the system applet. It can tell you what video you have. Take the time to look around and explore ;)
Go to the nVidia or AMD site depending on your finding. They provide up to date video drivers.
Whatever your source, you now have an executable package. Just double click it and the installation process will start.
If you are using Vista or Windows 7, you WILL be asked for right elevation. Enter the administrative acount password to continue.
Follow the on screen instructions, agree to the licence agreement.
You should decline any additional offers about accessories, tool bars and such. Those are NOT needed.
Accept the default install location and options.
Let the installer finish it's work and reboot when asked.