Cannot edit single NURBS curve control points after changing its properties If I do the following:


Add a NURBS curve
Select a control point
Press N and change its y property to 0.0
Repeat this step for all the control points of the NURBS curve


Then I'm unable to edit the single control point: if I select a single control point and try to move it, the whole NURBS curve with all the control points are displaced. It seems like the curve becomes a whole object whose single points cannot be modified. If instead I just change the x,y,z values of the single control points through the panel they are edited singularly.
Sounds like you unintentionally pressed O key by accident and turned on Proportional editing.

Try disabling it in the 3D view toolbar at the bottom of the screen