some amount of detail on your question would help arriving at
solution.
for experimenting, i created a combobox in sheet1 in book1 and passed
range to it from sheet1 in book2.
Private Sub ComboBox1_MouseDown(ByVal Button As Integer, ByVal Shift A
Integer, ByVal X As Single, ByVal Y As Single)
Sheet1.ComboBox1.AddItem "([Book2.xls]Sheet1!R1C1:R8C1)"
End Su