video will only play once

[Louh]

I am trying to include a large wmv file (one hour) in a project. I published the initial build as a test. The first time I opened it, it began playing fine. I closed it after a couple of minutes, feeling really successful. Then I tried to open the video again, and it would not run...no sound or picture. Any idea about what I have not done?
I am using Window's Media Player 10. Thanks! Louh