Ok lets see if this will help
1. uninstall all your sound drivers (you do have the drivers for the new card ?)
2.remove sound card
3. reboot and enter your bios make sure its set to PnP os
4.Shut down and replace s/card
5. Reboot and enter bios again go to PnP Devices check what is there and there irq's
6. enter the irq next to your s/card ( 5 is default) you can use 7, 9 or 10
7.reboot and i hope it works