Steps to show or hide the taskbar clock in Windows XP.
1. Right + click any open area on your taskbar.
2. Choose Properties. This will open the Taskbar and Start Menu Properties menu. Makes sure the "Taskbar" tab is selected.
3. Under "Notification area" checkmark Show the Clock or unceck the option to hide the clock.
4. Click on Apply
Note: To hide the Windows taskbar clock simply uncheck "Show the Clock" and apply.