If you have several columns hidden (i.e. columns G:K) and you want to unhide just one (i.e. column H), here’s a trick that will avoid you having to unhide all the columns first and rehide the others.
In the name box (the small white box to the left of the formula bar) type a cell address that is in the column you want to unhide. In this example, H1. Cell H1 will be selected even though the column is hidden. Now, from the Format menu select Column, Unhide. Just column H is unhidden.
The same trick will work for unhiding a hidden row.
To unhide column A in the worksheet in Excel versions 97 to 2003