No sound with Windows 7 beta

Depends on what audio chipset your MBP uses. Realtek?

Google or Softpedia are good start (also Guru3D).

The tip for using compatibility driver installation is common and needs to be used for many programs and drivers.

I posted a thread this AM with a couple links, incl where to get some drivers and such.
http://discussions.apple.com/thread.jspa?threadID=1866970&tstart=0

Excellent RSS of Windows 7 blog articles.
http://windowsteamblog.com/blogs/MainFeed.aspx

blog dedicated to the engineering of Microsoft Windows 7
http://blogs.msdn.com/e7/default.aspx

Had problems re-installing RealTek drivers following the above instructions.

Kept coming up with some sort of initiation error and fail to run. This happened whether it was with the RealTeksetup drivers on the OS X install disc or the updated R2.14 from the RealTek website.

Managed to solve this problem by reinstalling the realtek drivers with Windows 7 running in *Safe Mode* and it worked.

So if you're having a similar problem then do try re-installing under Safe Mode.

For those who don't remember, you initialise Safe Mode by holding down F8 as Windows is starting up.

This guys link led me to a post that helped me fix the problem.

Use Vista Compatibility Mode; or Troubleshoot (control +click on installers) and it will guide you through.

Someone said they modified .msi installer itself to always use Vista mode.

There is no need to install in Safe Mode, and some drivers won't at all.