Hey,
You change the driver in the setup page of whatever program you're using, probably the same page where you told your programs to use the Revolution.
Don't sweat this one too much, all the stuff you're doing right now (configuring your card with your program) is really basic, and it should be the absolute first thing you do when you install a new program or piece of hardware. It only takes a few seconds, and it is always in the first chapter or two of any software manual; read your manuals and follow the instructions.
Think of it like this: you have a TV, and it works fine with your video player, satellite, cable, Playstation, etc. However, one day you decide that you want a bigger tv, so you run out and buy a new one.
After unplugging everything from the old tv, removing it, placing the new tv and plugging everything back in, you turn it on...
"Wait!", you say, "nothing works!" You have snow, no volume, and the remote looks different. "I don't understand, my stuff USED to work with my old tv!" What do you do? You have to read the manual to figure out how to set the tv up to receive channels from the cable/satellite and how to switch between the different inputs for the video/DVD/game console.
I'm sure this has happened to you sometime in the past, maybe not with a tv, but with something else...it's the same with computers, when you install something new, you're having to deal with different drivers, different software, different configuration...it will take a few tries to get it right, but once you do you leave it alone and you're good to go.
Take care,
Nick