You can easily download Apple Quicktime 7, for free.
http://www.apple.com/quicktime/download/
Quicktime will play your video which is actually a .mov format, an Apple MPEG 4 video format. Windows 7's Windows Media Player 12 also supports the .mov format, and will play these videos fine. It doesn't look like Microsoft is going to release Media Player 12 for Vista however.
Garydp makes a very good point about being able to view file extensions. You should definitely think about unchecking the Hide extensions for known file types box in the View folder options section. Knowing the file extension could have lead to a successful Google solution right off the bat.