Step 1 : Open Device Manager and open display dapters.
Step 2 : See what make and model the graphics card is.
Step 3 : Go then to the Manufacturer's Website : www.nvidia.com / www.amd.com / www.intel.com
Step 4 : Search for your models Drivers and download them.
Step 5 : When the dowload is finished,run the dowloaded file