Well, by uninstalling the sound driver and not replacing it with another one, now you have no sound capability whatsoever. So it's not surprising Tron 2.0 doesn't want to work any more. You'd have to disable sound in the game launcher, to make it work again.
Though, Vista should detect that the sound driver is missing, and try to install it again automatically. The problem there, is it will try to download and install the latest. Which seems to be what was causing the problem in the first place. What you need, for now, is an older version of the Realtek driver.
As I understand it, you're using the HD Audio codec chip from Realtek. The latest HD Audio codec driver from Realtek is v2.02. And according to what I've read, 2.01 and 2.00 both were released within the last couple of months. When did the problem start?
http://drivers.softpedia.com/get/SOUND-CARD/REALTEK/
Look on that page, and download the "Realtek High Definition Audio Codecs Rx.xx Vista" file that's dated prior to when the problem started. Install that, and see what happens.
And in the future, when you do Windows updates, you'll have to specify that you don't want to download the latest Realtek driver. Or else the problem could come back.
Hopefully, installing an older Realtek driver will cure your problem. When Layer told me about this same problem he'd had, he said that reverting to an older Realtek driver cured it.