Forgot password for excel sheet . . How to break it ?

Open the workbook that has the protected sheet in it. Hit Alt+F11 to view the Visual Basic Editor. Hit Insert-Module and paste this code into the right-hand code window:

Sub PasswordBreaker()      Dim i As Integer, j As Integer, k As Integer

  Dim l As Integer, m As Integer, n As Integer

  Dim i1 As Integer, i2 As Integer, i3 As Integer

  Dim i4 As Integer, i5 As Integer, i6 As Integer

  On Error Resume Next

  For i =65 To66: For j =65 To66: For k =65 To66

  For l =65 To66: For m =65 To66: For i1 =65 To66

  For i2 =65 To66: For i3 =65 To66: For i4 =65 To66

  For i5 =65 To66: For i6 =65 To66: For n =32 To126                 ActiveSheet.Unprotect Chr(i) & Chr(j) & Chr(k) & _

      Chr(l) & Chr(m) & Chr(i1) & Chr(i2) & Chr(i3) & _

      Chr(i4) & Chr(i5) & Chr(i6) & Chr(n)

  If ActiveSheet.ProtectContents = False Then

      MsgBox "One usable password is " & Chr(i) & Chr(j) & _

          Chr(k) & Chr(l) & Chr(m) & Chr(i1) & Chr(i2) & _

          Chr(i3) & Chr(i4) & Chr(i5) & Chr(i6) & Chr(n)

   ActiveWorkbook.Sheets(1).Select

   Range("a1").FormulaR1C1 = Chr(i) & Chr(j) & _

          Chr(k) & Chr(l) & Chr(m) & Chr(i1) & Chr(i2) & _

          Chr(i3) & Chr(i4) & Chr(i5) & Chr(i6) & Chr(n)

       Exit Sub

  End If

  Next: Next: Next: Next: Next: Next

  Next: Next: Next: Next: Next: Next

End Sub

Close the VB Editor window. Navigate to the worksheet you want to unprotect. Hit Tools-Macro-Macros and double-click PasswordBreaker in the list.

you can use office Password Recovery software to Reset Password

here is the link  Office Password Recovery