This code will cycle through and entire list of files that meet the *.xls criteria within the specified folder. You should be able to drop your formatting code into the area indicated.

Private Sub CommandButton1_Click()
Dim ws As Worksheet, Path As String
Path = "C:\temp\"
Set ws = ActiveSheet
Filename = Dir(Path & "*.xls")
Do Until Filename = ""
Workbooks.Open Path & Filename
Your code here
Filename = Dir
Loop
End Sub