Here's the problem. I have a new, clean installation of Windows 7 with two user IDs. One of the IDs was running the game Modern Warfare 2. I "switched user" to the other ID and opened the NBC Olympics website to watch video of events. The NBC site uses Silverlight for video playback. When I started a video, two audio streams played, one from the video and the other from the game running on the other ID. The game audio did not play until the video started, and it stopped when I closed the NBC web page. When I switched back to the ID with the game, a dialog popped up about DirectX encountering an error and the game crashed. I couldn't find any event log entries about the crash, but audio "bleed" such as this should not be happening.

I agree with you that what you experienced should never happen, but given that games often circumvent the normal processes in the operating system in pursuit of performance, are you sure it wasn't the game's fault, and not Silverlight? Frankly what you're trying to do - run two things simultaneously on one system using two different user accounts - is kind of way out there for Windows. While Microsoft may have anticipated this in the design of their multimedia services, I guarantee you the game designers did not. That's just not something game designers would expect you to do! -Noel

I have no way to determine if the game is at fault or not. One clue, however, was that there was no sound from the game until a Silverlight video started up in the active session. That suggests to me that Silverlight hooked into DirectX and the bug was the two audio streams being combined. I've used fast user switching both with XP and the Win 7 RC and until this had no problems of this sort.

The issue should be caused by the game. How does it work if you open another game? You may just save and close the game before browsing web pages. Arthur Xie - MSFT