Here is one way to find and flag your duplicates. However, there are many more approaches which can be found in the FAQ on MrExcel and on the web by searching on "Find Duplicates Excel VBA".
Dim sh As Worksheet, rng As Range
Set sh = Sheets(1) 'Edid sheet name
Set rng = sh.Range("B2:B151")
For Each c In rng
If WorksheetFunction.CountIf(rng, c.Value) > 1 Then
c.Interior.ColorIndex = 15
x = x + 1
MsgBox "There were " & x & " cells flagged as duplicates"