I can't seem to capture video into WMV anymore, only AVI?

Hello everyone, any help is appreciated.

I upgraded from XP to 7 about a year or so ago, and just noticed that the few home DV videos I captured since then were in AVI format, and about 12 GB each, compared to the former ones on XP which were WMV and not quite 1GB each. I have tried in vain to set the automatic capture on Windows Movie Maker to WMV as default, but it doesn't seem to allow it. Is there a workaround, or am I missing something? These AVI files are just too big for my storage space over time.

Thanks!