I just installed a audigy 2 sound card into my XP system and the computer isn't shutting down.
I press shut down and it will just sit there as if it never got the command. Any ideas?

Have you tried to make sure the drivers are up to date?

creative has a auto update service that you can use to get the latest driver automatically

http://us.creative.com/support/downloads/

Also for now try without the extra software just use the driver only...

I use a Audigy 2zs without any problems(minus the fact that the creative mixer needed to be set to run on one cpu for better performance)

I updated the driver up to date and I found out that the problem is that the computer is not shutting down, but shutting down really slow. It take more than a minute now.

did you install anything else? maybe uninstall the card and all software and just try the card and driver only?

And more info on your system...
System specs
ect