find and replace crashes when value is not present.

hello,

I created a macro that I want to use across all my workbooks, it finds abbreviation and replaces it with the full name. Unfortunately it crashes when the abbreviation I am looking for is not there. If anyone can help me I appreciate it. my code and the file is attached.

Sub rename()
'
' rename Macro
'

'
    Selection.Replace What:="bc", Replacement:="back curb", LookAt:=xlWhole, _
        SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, _
        ReplaceFormat:=False
    Selection.Replace What:="ea", Replacement:="edge asphalt", LookAt:= _
        xlWhole, SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, _
        ReplaceFormat:=False
    Selection.Replace What:="gr", Replacement:="guard rail", LookAt:=xlWhole _
        , SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, _
        ReplaceFormat:=False
    Selection.Replace What:="mh", Replacement:="manhole", LookAt:=xlWhole, _
        SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, _
        ReplaceFormat:=False
    Selection.Replace What:="mh", Replacement:="manhole", LookAt:=xlWhole, _
        SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, _
        ReplaceFormat:=False
    Selection.Replace What:="mhsa", Replacement:="manhole sanitary", LookAt:= _
        xlWhole, SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, _
        ReplaceFormat:=False
    Selection.Replace What:="sp", Replacement:="sign", LookAt:=xlWhole, _
        SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, _
        ReplaceFormat:=False
    Selection.Replace What:="cull", Replacement:="culvert", LookAt:=xlWhole, _
        SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, _
        ReplaceFormat:=False
    Selection.Replace What:="culs", Replacement:="culvert", LookAt:=xlWhole, _
        SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, _
        ReplaceFormat:=False
    Selection.Replace What:="pp", Replacement:="power pole", LookAt:=xlWhole _
        , SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, _
        ReplaceFormat:=False
    Range("F16").Select
    ActiveWindow.SmallScroll Down:=21
    Cells.Replace What:="ec", Replacement:="edge of concrete", LookAt:= _
        xlWhole, SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, _
        ReplaceFormat:=False
    Range("F42").Select
    Cells.Replace What:="ec1", Replacement:="edge of concrete1", LookAt:= _
        xlWhole, SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, _
        ReplaceFormat:=False
    Range("G42").Select
    ActiveWindow.SmallScroll Down:=18
    Cells.Replace What:="brg", Replacement:="bridge", LookAt:=xlWhole, _
        SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, _
        ReplaceFormat:=False
    Range("F57").Select
    ActiveWindow.SmallScroll Down:=12
    Cells.Replace What:="vw", Replacement:="water valve", LookAt:=xlWhole, _
        SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, _
        ReplaceFormat:=False
    Range("F73").Select
    ActiveWindow.SmallScroll Down:=12
    Cells.Replace What:="fhy", Replacement:="fire hydrant", LookAt:=xlWhole, _
        SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, _
        ReplaceFormat:=False
    Cells.Find(What:="usa", After:=ActiveCell, LookIn:=xlFormulas, LookAt:= _
        xlWhole, SearchOrder:=xlByRows, SearchDirection:=xlNext, MatchCase:=False _
        , SearchFormat:=False).Activate
    Cells.Replace What:="usa", Replacement:="undergrond sanitary sewer", _
        LookAt:=xlWhole, SearchOrder:=xlByRows, MatchCase:=False, SearchFormat _
        :=False, ReplaceFormat:=False
    Range("F86").Select
    ActiveWindow.SmallScroll Down:=21
    ActiveWindow.WindowState = xlNormal
    ActiveWindow.WindowState = xlNormal
    Cells.Replace What:="eusd", Replacement:="edge of unsurfaced driveway", _
        LookAt:=xlWhole, SearchOrder:=xlByRows, MatchCase:=False, SearchFormat _
        :=False, ReplaceFormat:=False
    Range("F106").Select
    ActiveWindow.SmallScroll Down:=18
    Cells.Replace What:="upw", Replacement:="underground power", LookAt:= _
        xlWhole, SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, _
        ReplaceFormat:=False
End Sub

Cells.Find(What:="usa", After:=ActiveCell, LookIn:=xlFormulas, LookAt:= _
        xlWhole, SearchOrder:=xlByRows, SearchDirection:=xlNext, MatchCase:=False _
        , SearchFormat:=False).Activate"

crashes at that line because "usa" is not present on the current workbook.