Device Manager, Device Properties. See if you can Roll Back the driver.
If not, go to your Computer MFG Site, Support/Drivers & download.
Thank you for your suggestions. After three hours of trying various installation methods from the ASUS website, and others I found through Google, I finally found I had the original installation CD and it worked. My attempts to use Drive Finder, Drivers for Free, Driver Genius and accessing the ASUS technical support phone number were completely useless.