Question

give all functions of F keys

Answer 1

F1-Brings up a Help window in many applications, including browsers, Microsoft Office and others
F2-Renames a selected object
F3-Opens search box in browsers
F4-Displays the Address bar list in My Computer or Windows Explorer (Windows XP)
F5-Updates the active Window. Useful to refresh a displayed page in a browser
F6-Cycles through the screen elements in a window
F7-Turn on/off Caret Mode (Firefox). Performs Spell and Grammar check (MS Word)
F8-Extend selection (MS Office)
F9-Updates fields (MS Office)
F10-Activates menu bar options
F11-Toggles between full screen and normal display in browsers
F12-Opens "Save as" dialog (MS Office)

Answer 2

Answer:

Function Key

F1 - Display help screen.

F2 - Highlight file or folder for renaming.

F3 - Open search tool.

Alt+F4 - Close the current window.

F5 - Refresh the contents of a window or webpage.

F8 - Boot Windows into Safe Mode by holding F8 during startup.