That still wont work... Unfortunately, unless the driver you installed comes with a special uninstall program, windows still keeps the driver, it just unloads it when you uninstall. You can install new drivers on top of it, but sometimes even that won't work. (Like for HID drivers, which are "always on")
I can't give you specifics but first do what the first poster did and uninstall the driver.
Now go to your "inf" folder in windows. You'll need to figure out which files in this folder were related to the driver you installed.(hopefully it's obvious by how they are named, if not, you may be screwed) delete those files and only those files. Now windows won't "remember" what the device is when you plug it in and will ask you as usual.
Hope that helps.