In order to make it more likely for you to get replies, I have moved your thread to a more appropriate forum. I have also retitled your thread in order to make it more descriptive.
Restart your computer.
At the first text on the screen, or immediately after the Dell logo appears,
press the <F2> key every three seconds until the message Entering Setup appears.
When the System Setup screen appears, press the <CTRL> and <F11> keys at the same time.
Use the arrow keys to correct the date and clock settings as needed.
Press the <ESC> key.
Press the <Y> key to Save Changes and Exit.
Your computer restarts.
If you mean restore the OS to it`s factory state,see HERE
If your having a password problem see rustam`s posts HERE
(ctrl.+f11) is the one i needed. thank you and all who helped me to understand my computer a little better , once again thank you all very much, rooster mc coy dublin ireland.