Kevsim:
Your column is part of a table.
The answer will depend on how you "hid" the column. If you hid it via dragging it closed... do the following:
Go to the View menu - Tables:Tablename (whatever is after the : is the current table, often the Entry table.), then select More Tables...
In the More Tables dialog box, select your current table and then the Edit button. A column that you hid by dragging it closed will have a 0 in the width column. Set it to 10, click OK and then click Apply. Column should reappear.
If you hid the column by using the "Hide Column" feature, it will remove the column from the table. Use the Insert Column feature to add it back into the table.
Hope this helps!
Jan