:confused: I need your expertise to understand what's going on in my house??

I live in a two-stories house with 4 bedrooms.

In one of our rooms, there is a very little air coming our of the vent! (WHY?)
This one has a very weak and barely noticeable flow.

The other vents are working very well.

What should I do?
Who should I call for help??

Thanks for your time.

It could be a loose or disconnect duct. It could also be a inline damper that is not adjusted correctly. It could also be a design flaw from when the house was built. You can look for these items or call a HVAC company to find your problem.
Before I would do anything I would make sure the air filter for your furnace is clean.