Concept video tips

Hello, Tribe.

I would like to get some advice on making a concept video for Windows 9. Mainly I would like to know your recommendations on any video software that is useful for this. Any ideas? I'd prefer free software, but I'd consider paying for something relatively inexpensive. Also, keep in mind that it should be pretty good at rendering metro-style interfaces.

So far I've been using PowerPoint 2010 and converting it to a wmv, but that doesn't work well for everything.

Thanks for any ideas!