If you want to highlight Character which meet with your Criteria , You can use the Below Code :
Sub HighLight()
Application.ScreenUpdating = False
On Error Resume Next
Dim cell As Range
Dim rng As Range
Dim st As String
Dim loc As Integer
Dim n as string
st = ""
Set rng = ActiveSheet.UsedRange
For Each cell In rng
If cell.Value <> "" Then
st = st & cell.Value
End If
Next
For i = 1 To Len(st)
n = Mid(st, i, 1) & Mid(st, i + 1, 1) & Mid(st, i + 2, 1)
If Asc(Mid(n, 1, 1)) > 64 And Asc(Mid(n, 1, 1)) < 91 And Asc(Mid(n, 2, 1)) > 64 And Asc(Mid(n, 2, 1)) < 91 And Asc(Mid(n, 3, 1)) > 64 And Asc(Mid(n, 3, 1)) < 91 Then
Cells.Find(What:=n, After:=ActiveCell, LookIn:=xlFormulas, LookAt:= _
xlPart, SearchOrder:=xlByRows, SearchDirection:=xlNext, MatchCase:=True _
, SearchFormat:=False).Activate
loc = WorksheetFunction.Find(n, ActiveCell.Value, 1)
ActiveCell.Characters(loc, 3).Font.ColorIndex = 26
ActiveCell.Characters(loc, 3).Font.Bold = True
i = i + 3
End If
Next
Application.ScreenUpdating = True
End Sub
