The windows at my cottage are double-paned. I have discovered condensation in between the two panes. What can I do to correct the problem?

I live in a two-story house that sits on concrete and does not have a basement. The living room is difficult to keep warm in the winter. All the hot-air vents are located on the ceiling. If I moved them down to the ground, would the room be better heated?

There is a cold-air draft that comes through the front door of my house on cold winter days. The previous owners installed weather stripping but it does not seem to be doing the job. What can I do?