PC Pentium 4 install my sound drivers

Hello,
I have pc pentium 4 wid windows xp sp2.i tries to intall drivers for my sound cars which is realtek ac97.bt em unable to intall it..i tried to intall frm internet too bt still problem is there.an error messenge cum that stop installation if u continu e it will cause errors in ur system.and them windws automaticlly reestars...
can any 1 plz tell me wat should I do?
if I install SP 3 will this problem slves??