Have what I think is a shift lock issue with excel. Think this is a function
i have inadvertedly turned on, perhaps whilst holding down shift key for too
long whilst typing. Right clicking/double clicking won't remove it.

Shift to create a capital no longer works.
When I tab it goes left instead of right.
Clicking with mouse anywhere highlights all cells in the area.
Trying to enter numbers enters their symbols instead.

Does anyone know what this function is? How i switch it off?