I have a HP Pavilion dv4000. I recently reinstalled Windows XP and now my audio is out. What do I do?

Before I reinstalled windows, my audio was acting weird. For example: I would switch tabs in Firefox and the audio from iTunes would become scratchy. Because of this(and some other stuff) I decided to reinstall Windows XP. After I got done reinstalling XP, I installed everything off the "driver and software" CD. Now I have no audio. Device manager says that there isn't a driver. I then told device manager to update drivers but the updater said that it couldn't find any. I then tried to find the driver manually at Altec Lansing's website but couldn't find it. I then went to HP's website and found a driver, sp29586, which is from Soundmax, but when I try to run that, IT says it can't find the driver. I don't know what to do and I'm just wondering if anyone has got an answer for me.