Some of my students have indicated that my videos aren't playing on Windows 7 with 64bit Windows Media Player. I've tested it myself on 3 different machines, and it works fine for me - and I cannot recreate the problem, so I believe it's a sporadic error.
First, try running a Windows Update. This may correct the problem. Some PCs are still running the ORIGINAL release version of Windows 7, and there were some bugs in there.
If that doesn't work, try manually downloading the latest version of Windows Media Player, which you can get from Microsoft's web site here:
Another alternative is to download the Windows Media 9 Codecs manually. Yes, I know you have a newer version of Windows Media Player, but all of my videos were COmpressed with WM9 and so you need to DECompress them with the WM9 Codec (which is what a CO-DEC does). You can download the Codecs here:
I think the problem may be that Microsoft (in their infinite wisdom) isn't distributing the older WM9 Codec with the newer versions of Windows Media Player. Some systems, however, are able to automatically download the Codec from Microsoft's web site and don't have the problem. Other systems can't (if they're offline, behind a firewall, etc.). This is probably where the problem is coming in.
Now, if those solutions don't work, you can try downloading the VLC Video Player. It's a free open source player and a couple other students who were having trouble playing my videos on 64-bit WMP said it fixed the problem for them. Here's a link:
You should be able to play the videos right out of your Documents/599CD folder - and sometimes this even makes WMP work because it installs new CODECs. Let me know if that works.
If that STILL doesn't work, I've converted many of my courses over to Flash video as well. You can watch the lessons online in the Theater by clicking on the FLASH PLAYER option in the bottom left part of the Window.
Let me know which, if any, solution fixes the problem for you. I'm anxious to nip this in the bud. Microsoft did something like this previously when Windows Vista came out. None of my software worked and I had to completely rewrite my Video Player.
Because of this, I'm seriously considering switching EVERYTHING over to Flash video in the future... but for now, I'm sure one of the above solutions will help fix the problem.