Just use
Dim Cell As Range
Columns("B:B").Select
Set cell = Selection.Find(What:="celda", After:=ActiveCell, LookIn:=xlFormulas, _
LookAt:=xlWhole, SearchOrder:=xlByRows, SearchDirection:=xlNext, _
MatchCase:=False, SearchFormat:=False)
If cell Is Nothing Then
'do it something
Else
'do it another thing
End If