If these flat files are always the same layout, you may want to record a macro
when you do it by hand the next time.

Start a new workbook.
Tools|macro|Record new macro
Do all your importing and reformatting.
Include all the things you like (worksheet headers, print headers/footers/freeze
panes/Data|Filter|Autofilter)

Stop recording and save that workbook with the recorded code in it.
Put a giant button from the forms toolbar on the first worksheet in that
"importer" workbook.  Assign your macro to the button.

You'll probably have to adjust the code a little to make it more generic.  When
you recorded your macro, you got something that looked like:

Option Explicit
Sub Macro1()

   Workbooks.OpenText Filename:="C:\myfile.txt", Origin:=437, StartRow:=1, _
       DataType:=xlFixedWidth, FieldInfo:=Array(Array(0, 1), Array(15, 1), _
       Array(41, 1))

End Sub

Well, instead of having your filename in the code, you can give the user a
chance to pick it themselves (take a look at getopenfilename in VBA's help):

Sub macro1A()

   Dim myFileName As Variant
   
   myFileName = Application.GetOpenFilename(filefilter:="Text Files, *.Txt", _
                       Title:="Pick a File")
   
   If myFileName = False Then
       MsgBox "Ok, try later"  'user hit cancel
       Exit Sub
   End If
   
   Workbooks.OpenText Filename:=myFileName '....rest of recorded code here!
   
End Sub

And you may need to adjust some ranges (depending on what you did when you
recorded the macro).  Post back with a snippet of your code (not the workbook)
and explain your problem.

But now whenever you need to import a text file with that layout, you can just
open your "importer" workbook and click the giant button.