have you got an onboard sound card as well? - if so turn it off in the bios.
If not install the latest drivers for your sound card as windows maybe installing incorrect drivers on boot up.
Have a look in "systems information" in sub-category "problem devices" and see what is listed.
Basically it sounds like one of your drivers or hardware is corrupt which has upset your system and causing boot problems - its a matter of finding which driver or hardware that is causing the problems - it may not necessarily be your audio drivers but something like your mother board drivers