Lines not working ?

I am now getting used to the system, but halfway through a drawing, when I select lines, it does not work.
It is like line control is locked. I had this before with another drawing and same thing happened.
Mike.

Maybe previous command wasn't finished properly. Try Esc Esc.
Or the layer is locked. The padlock symbol in the Layer List.

Thank you Dellus. I will check that out.
Is it possible to alter the dimensions to closer tolerances ?
Mike.

Play with settings in Options - Current Drawing Preferences - Units and Dimensions regarding Precision and Zeros.