Hi,
Eight hours is too long. It took me quite a few go's on my sons XP PC before it started. I kept plugging it in and out, and running the ugrade and then out of the blue the "access denied" box didn't pop up and the upgrade just started for no reason. I just left it alone to do it's thing and presto they now work perfectly with my ipad 2 (brilliant for watching movies). BTW make sure the USB cable small end has 4 or five plugs in it, you may need a magnifying glass to see. The first one I tried only had 2 in it!
Good luck, I know how frustrating it is, just stick with it :/
Cheers,
Inge