VBA to open, edit, save and close

I Need a VBA to open, edit, save and close a number of excel files in a given folder.
the cells i need to change are F5,I5 and P5. All cells are in the same place on each wookbook sheet, all the wookbooks are in the same folder. I have to update them from MIN to MIN1,MIN2 and MIN3 otherwise the consolidation does not work correctly. i would manually do these changes but its something that will be an on going problem.

SO far i just have a macro to do this but with 500 files at once to change it takes some time. I would prefer it to be automated.

PHP Code: 

Sub Macro1()
'
' Macro1 Macro
'
' Keyboard Shortcut: Ctrl+w
'
Range("F5").Select
ActiveCell.FormulaR1C1 = "MIN1"
Range("I5").Select
ActiveCell.FormulaR1C1 = "MIN2"
Range("P5").Select
ActiveCell.FormulaR1C1 = "MIN3"
Range("G5").Select
ActiveWorkbook.Save
ActiveWindow.Close
End Sub