I did the same thing ("...wiped Vista of my computer and installed it back on...") and I'm having audio problems as well. I have a High Definition Audio device and it said it was SigmaTel. I no longer have an audio output device installed b/c I can't seem to find anything that will work...
I've been having problems with my sound skipping every few seconds. Window Media Player said it was possibly the audio driver. I've been to several websites trying to find a solution that works correctly. No luck so far! Any suggestions?! Shanna