Have you tried removing your sound card and using the on-board audio? I know that it won't have the same sound quality, but it will eliminate (or otherwise) the card as being the cause of the problem. When you do install the OS, don't allow it to dynamically update during the installation. Always disconnect from the Internet until you have finished installing. I create a disk with the latest drivers, utilities and other useful programs/applications for my system (including the latest release of Avast!) which I then use to manually update my system prior to connecting to the Internet.