Although MS Windows (in its various versions) is at present the most popular OS (Operating System) in personal computers, after years of consecutive improvements there are still various issues which need to be improved, which include for example issues of efficiency, comfort, and/or reliability. The present invention tries to solve the above problems in new ways that include considerable improvements over the prior art. Preferably the system allows for example a "Reset" function, which means that preferably an Image of the state of the OS (including all loaded software) is saved immediately after a successful boot on the disk or other non-volatile memory and is preferably automatically updated when new drivers and/or software that change the state after a boot are added, so that if the system gets stuck it can be instantly restarted as if it has been rebooted. Other features include for example solving the problem that the focus can be grabbed while the user is typing something, allowing the user to easily define or increase or decrease the priority of various processes or open windows, a powerful undo feature that can include preferably even any changes to the hard disk, improved undo features in word processing, improved file comparison features, being able for example to track changes retroactively, improved backup features, and many additional improvements. The application covers also improvements that are related for example to Word processing (since for example in Microsoft Windows, Word behaves like an integral part of the system) and things that are related to the user's Internet surfing experience (This is important since for example in Microsoft Windows, Internet Explorer is practically an integral part of the OS). The invention deals also with some preferable improvements in the performance of the hard disk.