See solution in other versions of Excel:
Before trying the following solution, you might want to make sure that you don't have any frozen panes that you need to unfreeze:
Learn how to unfreeze panes in Excel:
Question: How do I unhide column A in a sheet in Microsoft Excel 2003/XP/2000/97?
Answer: Under the Edit menu, select "Go To".
When the GoTo window appears, enter A1 in the Reference field and click on the OK button.
Under the Format menu, select Column > Unhide.
Now you should be able to see column A in your Excel spreadsheet.