AVI & WMV thumbnails not displayed

(I originally posted this in Vista General Discussion but no response there.
I may be better suited here.)

All AVI and WMV files display an icon rather than a thumbnail image, both in
WMM and Windows Explorer.

JPG photos etc are all OK.

I have tried other suggestions from the forums, inclduing F5 and using disk
cleanup to clear the thumbnail cache.

The AVI and WMV files are correctly associated with Media Player.

Windows Media Center cannot locate the AVI and WMV files.

Any ideas on how to resolve?

PS. I omitted to mention that I'm running Vista Ultimate.

Addition of registry key below fixes the display problem for Windows Explorer
and WMM.

See
http://www.hanselman.com/blog/FIXMis...xp lorer.aspx

Scott's supplied REG file doesn't seem to work so ShellEx keys applied by
hand.

However files are still not detected by Windows Media Center.

Key Name: HKEY_CLASSES_ROOT\.wmv\ShellEx
Class Name: <NO CLASS>
Key Name:
HKEY_CLASSES_ROOT\.wmv\ShellEx\{BB2E617C-0920-11d1-9A0B-00C04FC2D6C1}
Class Name: <NO CLASS>
Value 0
Name: <NO NAME>
Type: REG_SZ
Data: {c5a40261-cd64-4ccf-84cb-c394da41d590}

Finally I copied the registry keys for .AVI, .MPG and .WMV from another,
almost identical PC. These keys do work and all display is now fine.

Key Name: HKEY_CLASSES_ROOT\.avi\ShellEx
Class Name: <NO CLASS>
Key Name:
HKEY_CLASSES_ROOT\.avi\ShellEx\{BB2E617C-0920-11d1-9A0B-00C04FC2D6C1}
Class Name: <NO CLASS>
Value 0
Name: <NO NAME>
Type: REG_SZ
Data: {c5a40261-cd64-4ccf-84cb-c394da41d590}