This macro from David McRitchie will make the ActiveCell the last cell. Select the cell you want, then run the macro.
I have used it many times with no problems.
Sub makelastcell()
'David McRitchie,
http://www.mvps.org/dmcritchie/excel/lastcell.htm
Dim x As Integer
Dim str As String
Dim xlong As Long, clong As Long, rlong As Long
On Error GoTo 0
x = MsgBox("Do you want the activecell to become " & _
"the lastcell" & Chr(10) & Chr(10) & _
"Press OK to Eliminate all cells beyond " _
& ActiveCell.Address(0, 0) & Chr(10) & _
"Press CANCEL to leave sheet as it is", _
vbOKCancel + vbCritical + vbDefaultButton2)
If x = vbCancel Then Exit Sub
str = ActiveCell.Address
Range(ActiveCell.Row + 1 & ":" & Cells.Rows.Count).Delete
xlong = ActiveSheet.UsedRange.Rows.Count 'see J-Walkenbach tip 73
'use of filters can interfer with column elimination
Range(Cells(1, ActiveCell.Column + 1), _
Cells(Cells.Rows.Count, Cells.Columns.Count)).Delete
Beep
xlong = ActiveSheet.UsedRange.Rows.Count + ActiveSheet.UsedRange.Columns.Count 'Tip73
rlong = Cells.SpecialCells(xlLastCell).Row
clong = Cells.SpecialCells(xlLastCell).Column
If rlong <= ActiveCell.Row And clong <= ActiveCell.Column Then Exit Sub
ActiveWorkbook.Save
xlong = ActiveSheet.UsedRange.Rows.Count + ActiveSheet.UsedRange.Columns.Count 'Tip73
rlong = Cells.SpecialCells(xlLastCell).Row
clong = Cells.SpecialCells(xlLastCell).Column
If rlong <= ActiveCell.Row And clong <= ActiveCell.Column Then Exit Sub
MsgBox "Sorry, Have failed to make " & str & " your last cell"
End Sub
This macro is set up to delete all rows and columns past the active cell, not just the rows and columns past the active cell but limited to the used areas. This appears to be the only way to guarantee the active cell becomes the last cell.
Color formatting that commences outside the new used area will be lost. Color formatting that starts within the new used area will extend beyond the used area.
All number formatting (includes characters) outside of the new used area will be destroyed no matter the point of origin.
If the resulting last cell remains beyond the active cell, it will be noted as an error. If the active cell is beyond the resulting last cell that is acceptable, and no data should have been removed before the active cell.