evidence of these cards being present will be of you viewing an image on the screen while it's plugged into the 'new' video card, and hearing sound from speakers plugged into the 'new' sound card.
you will want to go out to the manufacturer's websites and get the drivers from them. the built-in windows drivers are very basic to provide basic compatibility with a wide variety of hardware.
soundcard:
support.creative.com
video card:
http://www.nvidia.com/page/drivers.html
i assume you're using XP, to view information on the cards you'd do the following:
click on the start button
click on control panel
double click on administrative tools
double click on computer management
click on device manager, under system tools on the left
or,
right click on my computer, on the desktop
click on manage
click on device manager, under system tools on the left
your video card will appear under the heading display adapters
your sound card will appear under the heading sound, video and game controllers