The onboard soundcard failed on a 2 years old Acer with Win XP, so I disabled it, fitted then installed a Soundblaster card with the CD supplied, (usually very reliable) which also did not work, it was disabled. I tested the card in another PC, it installed from the CD first time. I tried again on the Acer with antivirus disabled. Uninstalled first then reinstalled, the driver is shown in device manager as working, but in Sound Properties, the volume is disabled. Help please?