Follow the steps in the Update Driver Software wizard.

If you’re stuck at too low a resolution, are experiencing graphical artifacts or black screens, or your system is slow, you may not have the correct video drivers.
Windows 7 users can reinstall their video drivers by following these easy steps:

1. Open the task manager by right-clicking on the taskbar and clicking Start Task Manager
2. Under the Processes tab, click explorer.exe and click End Process. This is to clear up any graphical glitches
3. Under the File menu, click New Task
4. Type explorer.exe in the Open box and click OK
5. Click Start, then type Device Manager in the box and press Enter
6. Select the arrow next to Display Adapters and right click on the name of your video card. Click Update Driver Software…
7. Click Search Automatically to look online for new drivers

Make sure to restart your computer after the reinstallation of your video driver has completed.
Note that Update Driver Software often doesn’t find the latest video drivers. To get the best driver for your video card, try out Driver Reviver.