IIRC windows doesn't run ntp by default, it runs some propretary w32time service instead. I think it has an ntp client built in, but I'm not sure if it can be an NTP server out of the box.

I've got what might be an unusual request-- I simply haven't ever tried to do it and manufacturer specs aren't helping much. What I'm looking for is a home-class router where the unit will also serve ...