Hi
you may use the worksheet_change event for this (not tested though)
Enter the following in your worksheet module:

Private Sub Worksheet_Change(ByVal Target As Range)
If Target.Cells.Count 1 Then Exit Sub
if target.address = "$E$5" and target.value <"" then
'invoke user form
end if
End Sub

--
Regards
Frank Kabel
Frankfurt, Germany

Paul wrote:
Hi XL 2000

I would like a UserForm to pop-up upon the user entering
worksheet cell E3.

Any ideas appreciated.

Thanks,
Paul