Find All Occurrences Of Value

I've got the code to change all the relevant cells, but cannot get it to stop looping. The data is a converted text to Excel document, so cannot filter on it.


Sub FindIt()

Dim rngFound As Range
Dim n As Range
Dim o As Range
Dim ProjName As String

ProjName = 0

With Selection.Columns("D:D").Activate

Do
Set rngFound = Cells. Find(what:="Do Not Use", after:=ActiveCell, LookIn:=xlValues, _
lookat:=xlPart, searchorder:=xlByColumns, searchdirection:=xlNext, _
MatchCase:=False) .....................