if you go to www.avast.com they have a free download that would help get rid of your trojans etc, failing that to format HDD put xp disc in pc start it up press any key when prompted you will be given the option to format your drive, and do a clean install, but you also have the option of repairing the xp installation as well, your sound will be fine as you can download the driver if needed from the net
tony hull, December 2006