I recently reinstalled Windows 7 on my main box because I wanted to do some good screencasts for my PHP Video Tutorials site. After installing a few updates for Windows 7, I started getting a strange issue with audio and video. The OS would glitch. I would get short pauses in video and distortion in the audio.
After killing some processes and services, I soon found out that the problem was with Windows Superfetch. The issue has to do with my SSD drive. So if you have an issue like this and you have a solid state drive, you should try disabling superfetch. After stopping the service, give it a few moments. Play videos and see if you still get the problem.
If you want me to write up a howto on disabling superfetch, leave a comment. If there is any interest, I'll write it up.