I have the following function inside my module.
Function Colorize(myValue)
ActiveCell.Select
Selection.Font.Bold = True
Colorize = myValue
End Fu
A UDF will only return a value it won't allow you to change the properties of a cell/sheet/workbook. Move your code to a Worksheet_Change event or similar to change properties.
Eg
Private Sub worksheet_change(ByVal target As Range)
target.Font.Bold = True
End Sub
I use
chartRange = xlWorkSheet.Rows[1];
chartRange.Font.Bold = true;
to turn the first-row-cells-font into bold. And it works, and I am using also Excel 2007.
You can call in VBA directly
ActiveCell.Font.Bold = True
With this code I create a timestamp in the active cell, with bold font and yellow background
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
ActiveCell.Value = Now()
ActiveCell.Font.Bold = True
ActiveCell.Interior.ColorIndex = 6
End Sub