Media Center in Windows 7 has been running great for me for the past few months since I switched to Windows 7. I can watch HD content on my Xbox, and I have had very few issues with it (occasionally it has locked up on the Xbox, but restarting the Xbox usually fixes that). All of a sudden it has gotten jerky, SD content playing on my computer (not even streaming to the Xbox) is Jerky. VLC and Windows Media Player play the same content perfectly, it is just when it is playing in Windows Media Center (whether streaming or not). Any ideas what could be the cause of this? And yes I have reboot several times...