This works for me


Option Explicit
Sub try5()
 
 Dim vFF As Integer, TempStr As String
 
 vFF = FreeFile
 
 Open "C:\users\daddy\downloads\Sample.htm" For Binary As vFF
 TempStr = Space$(LOF(vFF))
 Get #vFF, , TempStr
 Close vFF
 
 MsgBox Len(TempStr)
 TempStr = Replace(TempStr, "<br>", "<p></p>")
 MsgBox Len(TempStr)
 
 Open "C:\users\daddy\downloads\Sample.htm" For Binary As vFF
 Put #vFF, , TempStr
 Close vFF
End Sub