Pinball Secret - Extra Balls

Instructions - 

Type 1max at the start of a new ball to get extra balls.
 
Secret - Gravity Well
 

Stop Timer in Minesweeper

Instructions - Launch Minesweeper and start a game so the timer starts counting, then press the Windows Key + D to show the desktop. Now when you select minesweeper from the taskbar you can continue playing with the timer stopped.

Minesweeper secret

Instructions - 

Minimize or close all running applications. Launch Minesweeper, then type xyzzy. Next hold down either shift key for one second. Now when you move the mouse cursor over a Minesweeper square you will see a tiny white pixel in the top left corner of your desktop screen. 

Zooming in and out in Browser

Hold Ctrl key and use the up/down scroll of the mouse wheel to zoom in and out in any browser.
To reset to the origianl font size hold Ctrl key and press 0. (Ctrl + 0)

Changing Startup and Log-off screens

Startup Screen

1. Create a 320x400 bitmap in the root directory and name it LOGO.SYS
2. You can use LOGOW.SYS file in the Windows directory as a starter

Logoff Screens

Other Samsung Codes

 *#9998*4357# Help Menu
  *#9998*5282# Java menu (GRPS/CSD settings for JAVA server)
    *#9999#0# Monitor Mode
  *#9999# or *#9998*9999# Software Version
  *#8888# or *#9998*8888# Hardware Version
  *#9998*746# or *#9998*0746# or *#0746# Sim Infos
  *#9998*523# or *#9998*0523# or *#0523# Display Contrast

To unlock your phone

To unlock your phone put a sim from another company,
  now type *#9998*3323# it will reset your phone. Push exit and then push 7,
  it will reset again. Put your other sim in and it will say sim lock,
  type in 00000000 then it should be unlocked. Type in *0141# then

Unlock any phone Security code

‘Read the full post before trying this’

Think how worse wiill that be if you do not know the security code of your own cell phone?
i.e. If you have forgotten or If someone might have changed it.
Do not worry I will let you know about the procedure to unlock your locked Nokia(for other phones see the next method below this) phone with a “MASTER CODE” (Note: This wont work for some Models).
For NOKIA :-