Most Intergarted soundcards can be turned off in the bios. Should be under the intergrated hardware/periferals section . Find the option, use page up to change it from enabled to disabled. Use the escape key to return to the bios main screen and then save and exit. If you aint got an option to disable the soundcard then it must be turned off using jumpers. If there is an option to turn the bugger off but it dont work then your cmos battery must be screwed.
Whats all this about square pegs and round holes?