Today Microsoft has released two reliability updates for Windows Media Center:

KB981129 – An update to the TV tuner functionality in Windows Media Center is available for Windows 7

An update is available for Windows Media Center in Windows 7. This update fixes a deadlock issue that occurs when you use a TV tuner in Windows Media Center.

This issue may occur if you change channels fast and frequently (also known as "channel surfing"), in Windows Media Center.

These symptoms may be caused by other issues that are not related to this update. For example, you may receive similar symptoms when you try to query current state of a TV tuner or of a malfunctioning hardware device.

KB981130 – Install this update if you see low bit rate message on Windows 7 Media Center when watching live TV

On Windows 7 Media Center systems with analog tuner(s), customers may encounter low bit rate overlays.

The mechanism Windows 7 Media Center uses to monitor bit rate (signal) strength is overly sensitive in some scenarios, resulting in false detection of a low bit rate which triggers an overlay.  This update addresses how Windows 7 Media Center monitors the bit rate on systems with analog tuners.