Hi Loondawg,
1. How did you rebuild the Windows media player library?
Note: Try to follow the below steps to rebuild media player database and database cache files, if you have already tried the below then you may skip that step.
Method 1
Clearthe Windows Media Player database. To do this, follow these steps:
a) Exit Windows Media Player.
b) Click Start, type %LOCALAPPDATA%\Microsoft\Media Player and then click OK.
c) Select all the files in the folder, and then click Delete on the File menu.
Note: You do not have to delete the folders that are in this folder.
d) Restart Windows Media Player.
Note Windows Media Player automatically rebuilds the database.
Method 2 If this does not resolve the problem, clear the Windows Media Player database cache files. To do this, follow these steps:
a) Exit Windows Media Player.
b) Click Start, type %LOCALAPPDATA%\Microsoft and then click OK.
c) Select the Media Player folder, and then click Delete on the File menu.
d) Restart Windows Media Player.
Note Windows Media Player automatically rebuilds the database.
Method 3
Try to manually update the media art in the Windows media player and check.
If some of your albums are missing album art, you can manually add a picture of your choice. When you do so, the picture is embedded into the file, and the Player will always show the embedded file as the album art (as opposed to any album art that the Player may have downloaded from the online database).
a) Click the Start button, click All Programs, and then click Windows Media Player.
b) If the Player is currently open and you’re in Now Playing mode, click the Switch to Library button in the upper-right corner of the Player.
c) Browse to the album that is missing art.
d) Find a picture that you want to use for album art (the picture can be on your computer or on a webpage), right-click the picture, and then click Copy.
e) The original picture can be in any of the following formats: BMP, GIF, JPEG, PNG, or TIFF.
f) In the Player Library, right-click the album art box, and then click Paste album art.
A copy of the picture is embedded into each of the songs from that album. The copy of the picture is automatically scaled to the appropriate size and converted to the JPEG format before it is embedded in the file. The original picture file is not modified.
For more information refer the below link.
http://windows.microsoft.com/en-US/windows7/Add-or-change-album-art-in-Windows-Media-Player
Method 4
Run the Windows media player troubleshooter and check.
Open the Windows Media Player Library troubleshooter
http://windows.microsoft.com/en-US/windows7/Open-the-Windows-Media-Player-Library-troubleshooter
Hope this helps!
Halima S - Microsoft Support.
Visit our Microsoft Answers Feedback Forum and let us know what you think.