Ive installed two different sound cards and the same problem with each. I had the problem with Windows 98 and then upgraded to XP and the same problem. When the sound card is physically installed the computer locks up at the welcome screen in XP. A few times it has actually gone further but it now just locks up there. If it isnt installed at all the computer works perfectly. Ive tried deleting all the drivers and installing the updated ones from Creative (maybe that is the problem!) :) Thanks for any help offered.