If you need to cancel the latest changesassociated with entering and formatting text in the editor, the browser and so on., to do this, simply press Ctrl+Z. Also in the text editor MS Office Word there is a special button on the toolbar responsible for the abolition of the latest changes. Another possible option using the menu "edit", "Cancel". In this case, if you previously used to save the editing process of documents, return to the previous position possible.
If you need to cancel the last changes, associated with image editing in Adobe Photoshop, use the shortcut Alt+Ctrl+Z or click on the menu item "Edit", then in the dropdown menu, select "Step back".
If you want to restore the file, hit F12. If you have already saved changes, then it will end up impossible. When editing graphic files is generally best to create and edit their copies, and the originals stored separately. Also view the history of changes in a special table changes, which is available from the menu item "Window".
If you want to undo the last changes that affected the work of the PC (e.g. installing updates, programs, utilities), open the "start menu", select menu standard programs, then system tools and finally "system Restore". Before you will appear on the screen a large window recovery operating system, click on the program's calendar reference point save the settings before making changes to the system, roll back to this date.
Keep in mind that it is best to keep personal data that you used when working in applications over this period, as programs would be removed along with them. It can be various logins and account passwords, key files, links, and so on.