How to Change the PC Clock to 12 Hour Time

Changing the Format in Windows Vista
1. Click on the Windows icon (bottom left part of screen) to enter your 'Start' menu. Click 'Control Panel.' Select 'Clock, Language and Region' from the Control Panel menu.
2. Click 'Regional and Language Options,' and then select 'Customize This Format' when the dialog box appears. Click on the tab labeled 'Time.' Select 'hh:mm:ss tt' from the 'Time Format' box (no capitalization).
3. Click on 'Apply' to save your changes. The system clock will update to the 12-hour format.
Changing the Format in Windows XP
4. Click 'Start,' then click 'Control Panel.' Click on 'Date, Time, Language and Regional Options.'
5. Click 'Regional and Language Options,' and then click 'Customize.'
6. Click on the tab labeled 'Time.' Change the 'Time Format' to 'hh:mm:ss tt' (no capitalization).
7. Click on 'Apply' to save your changes. The system clock will update to the 12-hour format.