Media Player problem on Win2K AS

I'm working on an MS cert right now, so I have the Win2K AS trial loaded right now. I got the OS installed fine, updated my drivers, got DirectX 8.1 installed and installed Media Player 7.1, but it keeps locking up. When I double-click a video or audio file, it will play it all the way through to the end, but as soon as it starts playing it stops responding to input. I can't hit the stop button, can't select the menus, nothin. The only thing that has any effect is if I hit the close button in the top right corner. Then it pops up a window that says that the program is not responding and allows me to select "End Now." Once that has been done, Media Player no longer opens when I double-click a file. The same thing happens if I open itfrom the start menu and do File->Open to select a file. I have tried reinstalling over top of the current installation, and I've tried completely uninstalling and reinstalling. Nothing works. It worked fine when I was running Win98. I need to get this working so I can view the videos that come with my courseware. Thanks in advance.