No Sound on PC

Me again… My computer had a virus,So i let my neighbor try to get rid it. I basically told him to erase everything n my pc, which he did, but when I got it back there was no sound, And I cant use the Usb, to download music in my Ipod, because this message of “put serive pack 2 disc in. So does this mean he didn’t install the Xp in properly, or he didn’t finish. What should I do? reinstall Xp> I don’t know . It just has been really irritating because Music is my life!!!!

Thank you again