Type one of the following (as appropriate) into the Name Box (the empty
field to the left of the Formula Bar)...
For XL2003 or earlier ==> D:IV
For XL2007 or XL2010 ==> D:XFD
Then right-click anywhere within the now selected cells and click on Hide in
the popup menu that appears. You may have to use the horizontal scroll bar
to move Columns A thru C back into view afterwards.