Is it me? Chaintech& ati

I bought a second-hand computer for my son and foolishly decided to update it to Xp, not realising that it had an ATI Rage 128pro game board in it. Not compatible, I found out. When I finally managed to retrieve ATI, I found no sound! No drivers! Having delved into the guts of the computer, I appear to have a chaintech AJA2E motherboard with via audio chip? VT82C686B. I'm in unchartered territory here- Can anyone give advice on how I get the sound back? I'm not yet a computer nerd, but I'm getting there fast. Incidently, can anyone recommend an idiot's guide to BIOS/CMOS and all that stuff?