I need multimedia audio fixed on my hp xw8200

Hello,
i recently was on a torrent site.
i was in the process of downloading 'faith no more live at download 09'
and I realised I may be downloading a file that was infected.
so I went through and deleted all the files I had downloaded and now I have no sound and
my multimedia audio controller in the manager devices has a yellow question mark.
and I went to try to update and download drivers from the hp site and nothing works.

i think I have a virus but dont know.
i ran a scan and caught something but deleted it and not sure if it was even related to this.....

can someone please help!!??

what do I do???
anything please.............