Use of Function Keys(F1-F12) to make your work easier !

F1 : Help for anything
F2 : Rename any file 
F3 : Search anything
F4 : Exit instantly pressing together Alt + F4 . In windows Explorer you can go to address bar by   pressing once !
F5 : Refresh a browser webpage Ctrl+F5.In PowerPoint,it starts a slide show,finds anything,works to replace,go to dialog in all Microsoft Office programs.
F6 : It works as a tab key,toggles between the menu items and workspace.
F7 : Caret browsing in firefox
F8 : In windows boot process F8 redirects you into the Windows Start Menu 
F9 : It is used in programming compilers;specially in Integrated Development Environments ; IDE in short.Ctrl+F9 compile and run the code.
F10: Use Shift + F10 to get mouse right-click context menu.
F11: It make changes to full-screen mode in Windows Explorer & browsers.In Microsoft Excel,Shift + F11 is used to add a new sheet,Ctrl + F11 is used to add a new macro to the workbook.
F12: Opens Microsoft Word save as .