Sorry I am not sure I understand what you are asking. Are you able to expand on your question and provide some more information please ? You need an operating system such as Windows 7 in order to use the computer, so do not delete it. if you are merely talking about Windows 7 updates when you already have Windows 7 some of those may be removable, some may not. If you have paid for an update from say Vista to Windows 7 then that may be rather difficult to reverse and not the sort of thing many users would wish to consider.