When you install a device driver on your computer, certain files get placed in a temporary directory on your computer. This is referred to as the driver "cache." These files are referred back to momentarily during the installation of the driver, but after that process is completed they have outlived their usefulness to you. If you want to clean the driver cache and get these worthless files off of your hard drive, you'll need to use Disk Cleanup.
Click "Start," "All Programs," then "Accessories."
Click "System Tools" and then "Disk Cleanup."
Click "OK" when asked to select which drive you'd like to clean up. By default your primary hard drive will be selected and, as this is where the driver cache is located, you don't have to do anything but click "OK."
Check "Temporary Files" and then click "OK" to clean your driver cache (as well as a few other directories simultaneously) and free up space on your hard drive.