1) Power on your PS2 Console, this is by pressing the 'Power/Reset' button down. Then quickly press the 'Eject' button on your console to stop the disc drive loading the inserted disc. This will make the console load onto the PS2 main menu.
2) Once the PS2 has booted onto the 'Main Menu', you will see two options 'Browser' and 'System Configuration Menu'. Using the D-pad found on your dualshock 2 controller, select the 'System Configuration Menu' option and press the 'X' button to enter.
3) Then the 'System Configuration Menu' will now appear onscreen on your TV. So using the D-pad, browse through the different options until you see the one called 'Screen Size'. When you have found it, select it and press the 'X' button on the dualshock 2 controller to enter.
4) You will now have three choices, '4.3', 'Full' and 'Widescreen'. Since you have a widescreen television, the option that you want to select is 'Widescreen'. This will make the PS2 system settings configure the console to display games and movies in the 16:9 widescreen aspect ratio.