Alt drag stopped working

Using the alt key to copy any object has stopped working. I click an object, then press alt key. The double triangle icon thing appears to indicate copy mode active.This indicates that it recognises the alt key. But when I release the object it does not copy. I've tried both alt keys but no difference. I've tried alt-drag and photoshop and that still works.

I also noticed that a similar issue is happening with shift key. For example, if using the line tool or the rectangle tool. I press shift and it applies as you expect - eg a straight horizontal line. I keep shift key held down and release the mouse. But even though the key is down it ignore the shift key rule and just draws the line where I released the mouse and therefore on an angle. And a rectangle does not stay square and so on.

My other programs on my computer still function as expected. Only happening with Illustrator - Version CC 22.0.1 (64-bit).

Driving me crazy! Please help.