I am trying to escalate this issue so M.S. will issue a fix for 64 byte machines. Without a codec or another player like VLC, WMP 12 is corrupted when working with MP4 files. The trouble shooter confirms this. I have fixed the corruption and am usying VLC.
The web is full of discussion about this problem with WMP 12, 64 byte and MP4 files.
There are some dangerous codecs out there and I respectfully suggest that M.S. apply a fix for this wide spread issue.
Microsoft is conducting an online survey to understand your opinion of the Technet Web site. If you choose to participate, the online survey will be presented to you when you leave the Technet Web site.