The Tragedy of Sound Software

My computer, a Vostro 200 Dell, has recently picked up a harmful rootkit while a family member was internet browsing on it.  I've completed many drastic measures to remove/locate this virus, but none has worked so far.  I may have to risk whiping out the hard drive and starting new.  Sadly, I don't have all of the hardwear disks due to moving.  Currently there is no sound on my computer.  Yes, it recognizes that there are sound drives, yes it says that they are working, and yes, they are plugged in properly and turned on properly.  There's usually a little icon in the right hand "action bar" as I call it, and after searching through it many times I can definitelly tell that the icon isn't there.  I can't for the life of me figure out where to get the hardwear to replace whatever it is that is needed for sound.  I have no clue what else has been lost or eaten by whatever virus(es?) that are being hidden by this rootkit.  Any suggestions?  (If you don't know anything about my softwear issues, then do you know about the rootkit issue?)