
i have had the same problem i just got windows vista yesterday i got premium edition with it so i installed and it said "please enter product key" i enterd it and it let me onto the next bit.
later that day i noticed that the sound wasnt working saying "no audio output device is installed". In device manager it is showing 2 sound drivers but still i hear no sound. If anyone knows how i can get my sound working give me an e-mail my address is jlsofit@hotmail.co.uk
Also it is saying "the product key you enterd is invalid" i went into "my computer" and you can re enter the product key i have done this several times making sure that i didnt type in the wrong code but its still giving me the message "the product key you enterd is invalid".