It's the software part of a graphics card.
So, right click My Computer
select Properties
select Hardware tab
click the Device manager button
There should be an expandable menu in here called "Display Adapters". Expand it.
If it's NVIDIA, then
go here and select the model you have, and install it
If it's Radeon, then
go here and select your model. and install.
The reasoning for this is, your display adapter may not be compatible with your DX version, so updating it may help