Excel program keeps freezing when I left-click on a cell.

[Lucci]

Each time i open a new or old excel spreadsheet, the cursor freezes as soon
as I left-click on a cell. I can't use the cursor. The entire column is
highlighted (then other columns as well) when I move the mouse. I cannot use
the Esc key to release. I have to use ctrl alt delete to end the program.