I'm not sure this will help, but in my case it wasn't the latest drivers, or not, it was the right drivers. I tried a dozen different downloadable drivers (wishing I could find the box and disc that came with the card the whole time), and nothing worked. I then went directly to the manufacturer's website, and even that didn't work. At someone's suggestion I removed and reseated the card, and that didn't help either. While I was doing that I read the name on the card itself, and realized I had gone to the wrong manufacture.
A quick trip to the people who actually made the card got me the drivers that did the trick.