How about a little macro:

Option Explicit
Sub testme01()

   Dim iRow As Long
   Dim iCol As Long
   Dim FirstRow As Long
   Dim LastRow As Long
   
   With Worksheets("sheet1")
       FirstRow = 1
       LastRow = .Cells(.Rows.Count, "A").End(xlUp).Row
       
       For iRow = FirstRow To LastRow
           For iCol = .Cells(iRow, .Columns.Count).End(xlToLeft).Column _
                         To 2 Step -1
               If Application.CountIf(.Cells(iRow, 1).Resize(1, iCol), _
                                          .Cells(iRow, iCol).Value) > 1 Then
                   .Cells(iRow, iCol).Delete Shift:=xlToLeft
               End If
           Next iCol
       Next iRow
   End With
End Sub

If you're new to macros, you may want to read David McRitchie's intro at:
http://www.mvps.org/dmcritchie/excel/getstarted.htm