Dim matchRange As Range, firstMatchRange As Range
Set matchRange = ws.columns(COLUMN_TO_SEARCH_IN).Find( _
        What:=VALUE_TO_SEARCH_BY, LookIn:=xlValues, LookAt:=xlWhole, _
        SearchOrder:=xlByRows, MatchByte:=False)
' Don't forget that the match will be the cell only, you will need
' to get the entire row from that for usual processing.

' Check if there's a match at all
If Not matchRange Is Nothing Then
    ' Memorize first match to be able to recognize whether we've got
    ' back to start
    Set firstMatchRange = matchRange
    Do
        ' ... DO PROCESSING ON THE MATCH...

        ' ...and jump to the next one
        Set matchRange = _
                ws.columns(COLUMN_TO_SEARCH_IN).FindNext(matchRange)
    Loop While Not matchRange Is Nothing And _
            matchRange.Address <> firstMatchRange.Address
End If