In buy mode or build mode, or in create a sim, actually even when sitting on the start screen the volume of the music increases. Like, steadily increases, until it's too loud to have a conversation over. There's nothing I can do besides exit build mode and the re-enter it to reset the volume. I don't even have the music up loud in the settings!

make sure your sound drivers are all up to date

I'm running XP, and every driver I have is up to date

I've got vista all my drivers are updated and have been since I installed. No sound works anywhere in the game but everywhere else on my computer. The reallyodd thing is the first time I played it the sound worked - now nothing. I saw on another website to do something with some files in the game another user said it worked for them. I was told on two separate forums to try this but it didnt work for me, is there any reason the sound does this?

Ditto. My sound worked the first time I played and that was about it.