If you are setting a Vista Virtual PC image up in Virtual PC 2007 you’ll soon realise that the audio doesn’t work. You’ll do a bit of Googling and find that Virtual PC 2007 has a ‘special’ audio set up just for Vista but good luck to you finding information about how you actually get it running. I eventually stumbled on the answers.
It turns out that when you install the Virtual Machine Additions, the sound drivers are copied to “C:\Program Files\Virtual Machine Additions”. They aren’t actually installed, just stuck in there. So, go to Device Manager and ‘update’ the driver, tell it you have the disk and point it to the path above.
Job done…