To update the time on your computer
If your computer is a member of a domain, your computer clock is probably synchronized automatically by a network time server If your computer is not a member of a domain, your computer's clock is automatically and regularly synchronized by an Internet time server. This procedure provides information about synchronizing your computer clock immediately.
Make sure you are connected to the Internet.
Open Date and Time in Control Panel.
Click the Internet Time tab.
The Internet Time tab is not available if your computer is a member of a domain.
Click Update Now.
To open Date and Time, click Start, click Control Panel, click Date, Time, Language, and Regional Options, and then click Date and Time.
Internet time synchronization updates your clock on a regular basis. Windows sets synchronization to occur weekly, but if you purchased a computer with Windows XP installed, your computer manufacturer may have set it to occur more often.
An Internet time server updates the date set by your computer as well as the time.
The Update Now button is not available unless the Automatically synchronize with an Internet time server check box is selected.
You can change the time on your computer clock manually by double-clicking the clock on the taskbar Under Time, use the arrow keys to change the time.