win7 Windows 7 and m4a Problem

[BoomyBoy]

I'm having a weird problem with my Windows 7 Ultimate. File Explorer doesn't recognize m4a associated files anymore. The problem is it doesn't show any information about m4a files. I can't see embedded album arts of m4a files or artist or album names. I didn't have this problem until I installed Windows 7 updates last night and removed Real Player. I tried to clean the thumbnail cache but it didn't work. I haven't had any problem like this before. What could be the reason? Thanks in advance:)