This is a very easy and straight-forward 2-step process to get quicktime (.mov) videos to play in Windows Media Player in Windows 7 (tested in WMP 12, Win 7 x64 — may also work for other WMP/Windows versions). You need to do both steps, and in this order.
Download and install QT Lite (it installs only the needed quicktime filters).
Download and install QuickTime DirectShow Source Filter (it installs the filters needed for WMP to play such videos). P.S. The website providing this file requires you to sign up before you download. It just takes a couple of seconds.
That’s it. Any .mov file should play in WMP now (note that .mov thumbnails in windows explorer may not show up, though).