Search The Names

I am trying to write a macro which will look at a search term entered into cell C1, then if there is a defined Name in the search range (AM1:DA5000) which matches then then name will be outputted to listbox 1.

eg if cell c1 = Out
then listbox 1 would return the following names from the above range:
Out1
Out2
Outer
Siderout
Outsider

I have the following code, which will only return the first instance it finds:

Public Sub findnames()Dim c As Range, rngDim n As NameActiveSheet.ListBox1.Clearmystr = [c1].Value**** ****Set rng = Range("AM1:DA5000")************For Each c In rng****************For Each n In ActiveWorkbook.Names********************If InStr(c, mystr) > 0 Then************************************ActiveSheet.ListBox1.AddItem c****************** ******************************************** End If****************Next n************Next c********End Sub