Microsoft has released the February 2008 Cumulative Update for Media Center for Windows Vista. I would expect the update is included in Service Pack 1 for Vista as well as being on Windows Update
Addresses an issue that is introduced in KB941229 in which the UI freezes and becomes unresponsive. This issue occurs when you try to change the channels while you are watching live digital TV on Xbox 360.
This update replaces the 941229 (http://support.microsoft.com/kb/941229/) October 2007 Cumulative Update for Media Center for Windows Vista
It will be on Windows Update
More details from Microsoft: February 2008 Cumulative Update for Media Center for Windows Vista
Ian Dixon is a Microsoft MVP (Most Valuable Professional), founder of TheDigitalLifestyle.com tech site and producer of the weekly The Digital Lifestyle Show podcast. Ian has been writing and talking about Windows for over 10 years and has over 20 years in IT as an IT Manager. Ian thousands of followers on Twitter and Facebook and over 4 million views on his YouTube channel.