Furnace not sending heat to front of 5W - Is it broken?

Usually the rectangular floor duct switches to one or two round pipes in the basement. Likely directly under the stairs. The clamps may be loose and the pipe fallen off. Or there may be something inside the pipe. You will probably have to remove the rear basement wall partition to check the connection.

This assumes you have the propane furnace running. If you are only using the heat strip in the AC, meaning heat is coming from the ceiling vents, then you need to switch the Tstat to get the furnace running.