can a satalite be fixed above any point on the earth's surface?

Answer 1

Sure, as long as you can afford the tow truck. so to speak.

Answer 2

Nope.
Only above the equator.

The satellite has to spin all around the earth, not just in the top half, or to one side. If it just happens to spin around a point that is spinning the same way at the same speed, then the two points follow each other. For this the satellite must be at the correct height else it will go to fast or too slow (need 24hour orbit).
Only above the equator satifies this.

You cannot stay above any other point without an engine, and we don't have the technology to keep that up for very long at present.

Satellites that are said to be fixed over say North America are actually over the equator below North America, with their antenna(s) pointed at North America. That's one reason Satelite communications is trouble over the poles, as the standard communications satellites are over the equator and can't see the poles so well.
The equatorial orbit can get crowded and new satelites need to be carefully positioned so as not to interfere with existing satellites.

Groups of satelites can also be arranged so that many are spinning around the earth in different paths, including over the poles. There may be more than 1 on each path so that all points always have at least one satellite in view (GPS needs 4 in view for XYZ+time calculations).

There are nets of communications satelites also, and these can be used over the poles. When talking via one of these satellites, you don't know it but your call is passed to consecutive satellites as each goes over the horizon and another comes into view. Similar to how you jump cell phone towers when on a phone call while driving in your car.

Answer 3

an nsa or cia one, yeah pretty much we can see alot.