For the first variant you will have to open the Properties dialog of the system drive (normally drive C). There you will press the button Cleanup. It will now take some seconds until the system has checked what kind of files can be safely removed and how many place would be recovered. Then a dialog will appear with a selection list of the different file types. Here you may have to scroll down to see the “Service Pack Backup Files”. Select them and press the OK button to start the removal process.