Click on the Device Manager tab then double click on Display Adapters. Highlight your adapter, and click the Properties button. An adapter properties dialog box will open. Take note of the name of the adapter and the manufacture. While the user's dialog box may not be identical to the one pictured, the same information should be present.
Several websites contain links to manufacturer's driver pages.
Open your web browser. Click on the link for a main search. Next, click on the first letter of the manufacturer's name. Link to the manufacturer by clicking on their name. Click on the driver link.