The majority of graphics card websites have 'auto-checkers' which can scan your system and find the correct card. They can be found here for the following makes:
AMD/ATI - http://support.amd.com/us/gpudownload/pages/index.aspx
Intel - http://downloadcenter.intel.com/
Nvidia - http://www.nvidia.com/download/index.aspx?lang=en-us
If you have the knowledge, we'd suggest using the manual download and install over the auto-checker, so if you know your exact graphics card make and the OS you are running, please enter in your details and find the latest drivers.
Bear in mind some laptops will have both Intel and an AMD or Nvidia driver, so remember to update them both when completing this process.
Once you’ve updated to the latest drivers and restarted your system you should be running the latest drivers available.
If you’re unsure about which card you have installed, please check your system manufacturers website.