Well since you have purchased a good board, congrats....
But 4 ur problem i advice to first setup one sound card only preferabily the onboard one.. if that works alright then you can be happy that there are no problems with the mobo...
Then if you can disable the onboard sound card from the bios or if not possible then delete it form the device manager shutdown and install the creative card (do not install the onboard one as it will try to after reboot).
Now see if it works fine..... if no then try the card at some frnds place to see it is not damaged....
Well it it works then install the onboard one....
this should help, as it did to a cousin of mine but he had a diff board but the same sound card... the problem is somewere in the resource allocation.
If it still doesnt work together then write a mail to Microsoft, creative and Asus with a CC to IT ministory of india(u can find it someware on
http://goidirectory.nic.in/) (more specific
mocit@nic.in --
http://www.mit.gov.in/ Dept of IT)specifiying your complete problem and system specs. All these products are PC platform certified so it is their head ache to help a consumer otherwise they can get into some serious Sh#T!
This 'nuskha' has helped me and a lot of my friends. I got replacment on a samsung HDD which they were not doing before and i kept on mailin and mailing them....
May the Force be with you.....