iWeb video problems

[msah]

I've created a website in iWeb and included Quicktime movies on several pages. The videos play fine on my MacBook Pro as well as other macs that I've tried, but they won't play on a PC. I added a link to QuickTime so that users can download the newest version of the QT player, but even after the player install, the audio will play, but the video will not. Any suggestions on what I'm doing wrong??
Thanks in advance.