Its a problem with all of creative labs drivers to date. It doesnt save the speaker config propely. You`ll probably find that its games that change it as well, on my rig, GTA3 and ST:BC always changes it from 5.1 to 4 speakers. Just just learn to live with it.
As for the hard lock. Never encountered that. Try DLing the latest driver set, or if you already have, re-install the sound card from scratch.
Also check, on the Creative labs website. There are some forums there that you can sometimes find the answer that you are looking for on.