hav a very foul smell coming from tghe vent in my kitchen floor, in the basement in the same spot under the kitchen it is the same foul smell, could ther be a dead mouse if so i cannot get to it , how to i get rid of the smell. Thank you to all.

If it's a dead rodent, the smell will eventually go away. You could try to remove the vent and snake a shop vac hose down it, but other than that only time will get rid of it. Now if you want to tear into floors and / or ceilings you can certainly replace the ductwork. But time usually takes care of the issue.

Sorry to sound like a smart __ _ _ but either wait it out or get rid of the foul, and the smell leaves with it.