Cell Selecting issue

Greetings,

Perhaps my first request was confusing. But this is really really driving me nutty. It's in Excel 2002

If I left click to select a cell, it sometimes puts a box around the cell and that's it. Other times it opens the cell and puts the cursor to the left of any entered data or just the cursor in the box if the cell is empty.

How I can I keep it just putting the box around the cell on single left click.

Thanks for the help.