I am still failing and I guess it is because I have not enclosed all the
code, so the problems must be somewhere else:
Sub TaylorFarm()
' Macro1 Macro
' Macro recorded 3/23/2006 by David Lanman
   Range("A1").Select
   Dim SerialNumber As String
   Dim rngFound As Range
   Cells.Find(What:="Equipment", After:=ActiveCell, LookIn:=xlFormulas, _
       LookAt:=xlWhole, SearchOrder:=xlByRows, SearchDirection:=xlNext, _
       MatchCase:=False, SearchFormat:=False).Activate
   EquipmentID = ActiveCell.Offset(1, 0).Value
   If EquipmentID = "" Then
     SerialNumber = ActiveCell.Offset(1, 3).Value & ActiveCell.Offset(1,
4).Value
     Sheets("TAYLORSerNo").Select
     Range("A1").Select
     Set rngFound = Cells.Find(What:="9C4754", After:=ActiveCell, _
LookIn:=xlFormulas, LookAt _
       :=xlWhole, SearchOrder:=xlByRows, SearchDirection:=xlNext,
MatchCase:= _
       False, SearchFormat:=False).Activate
       If rngFound Is Nothing Then
         MsgBox "Sorry, not found"
       Else
         rngFound.Select
       End If
   Else
     Stop      
   End If
   Cells.FindNext(After:=ActiveCell).Activate
End Sub

It fails when I try and do the Find "Set rngFound =". It is hardcoded here,
but I would be using the variable SerialNumber.

Thanks for your help.

Just my two cents - try removing Activate from the end of your set statement.

You're setting a variable, which you do not need to Activate it.  You can,
however, Activate it afterwards if you'd like, and that is only if it found
what you were looking for.  A simple test would look like this...

If rngFound Is Nothing Then
   Msgbox "Nothing was found!"
Else
   rngFound.Activate
   MsgBox "Cell found at " & rngFound.Address
End If