Show AM / PM symbol on the taskbar clock in Windows 7

By default, Windows 7 does not display the AM or PM symbol as it displays a 24 hour clock. To make Windows 7 display the clock in 12 hour format with the AM or PM symbol, perform the following:
1. Click Start button and then click Control Panel.
2. If the View by: is Category then click on Clock, Language, and Region and then click Region and Language. If the View by: is Large icons or Small icons then click on Region and Language.
3. From the Region and Language dialog box, click Additional settings... to open Customize Format dialog box.
4. Click on the Time tab. Under Time formats section, in the Long time: box, add tt to the end of HH:mm:ss. It should look like
HH:mm:ss tt (Make sure there is a space between s and t)
5. Click Apply and then click OK.