Stepping Thru Columns Beyond Col Z ( Into AA Etc)

I have some code which steps through a range of columns from A to Z ( using Chr(asc(col))+1 as the stepper.

This works fine until it encounters col AA then fails - I have added the function that does this - can you help me get beyond col Z?


Function findcol(strTitle As String, ws As Worksheet)
If Left(strTitle, 1) = "0" Then
strTitle = Right(strTitle, Len(strTitle) - 1)
End If
col = "A"
findcol = ""
While ws.Range(col & "1").Value <> "" And findcol = ""
If ws.Range(col & "1").Value = strTitle Then
findcol = col
End If

col = Chr(Asc(col) + 1)
Wend
End Function