It sounds like the ComboBox is used to present a series of choices to the
user and that each choice should launch a different algorithm for filling
those TextBoxes.
If this is so, then I'd go to the AfterUpdate event for that ComboBox and
use a Select Case Statement:
Select Case ComboBoxName.Value
Case Value1
TextBox1 = Value!
TextBox2 = Value2
Additional Expressions
Case Value2
TextBox1 = Value3
TextBox2 = Value4
Additional Expressions
etc.
End Select
John