Exporting from iMovie to work in Windows


I'm trying to export a QT movie from iMovie to work on a PC, but am not having much joy. I'm using the expert settings because the quality & file size I'm after is higher than the Web setting but less than the CD setting.
However, I'm finding that as soon as I choose any of the expert settings I get the desired quality/file size & the QT movie plays fine on my mac but doesn't play on a PC.
Has anyone experienced this before or can anyone recommend a solution?