Computer time is significant because your Windows XP operating system as well as other installed applications record user activities in log files. When time settings on your computer are incorrect, some applications may not function properly. You could also get confused as to when a particular file was created or modified. The following are some guidelines on how to change incorrect computer time on a Windows XP system.
- Confirm status of the Windows Time service. Windows Time is the operating system feature that controls your computer's internal clock. If Windows Time is disabled, some programs might not launch properly, or if it is in manual status, time and date has to be set every time you log on. The ideal and default setting for Windows Time is automatic. To confirm the status, right-click on My Computer and choose Manage. On the Computer Management window, expand Services and Applications on the directory tree located on the left pane of the window. Click on Services then look for Windows Time on the list that will appear on the main window. Under the Startup Type column, the service should be in 'Automatic'. In case it isn't, select this item then click on the Properties toolbar. Choose the correct setting on the Windows Time Properties dialog box.
- Synchronize to an Internet time server. Your computer's time can be automatically synchronized in two ways. It can use a local network server as a basis, or if doesn't belong to a network, use an Internet time server. Open the Date and Time Properties dialog box by double-clicking on the taskbar time display. Pull up the Internet Time tab and verify if the option 'Automatically synchronize…' is marked. Choose an Internet time server on the dropdown list, this could be either 'time.windows.com' or 'time.nist.gov' then click on the Update Now button. Your computer time will then update and synchronize and should now display the correct time.
- Change the time manually. The Date and Time Properties dialog box also allows you to manually change the time displayed. Pull up the Time Zone tab and choose the correct time zone for your area on the dropdown list. Proceed to the Date and Time tab, and then place the cursor in the input field under the graphical clock display. This will enable you to type in the correct hour, minute and choose between AM or PM. If necessary also adjust the date by choosing the correct month and year on their corresponding fields and clicking on the right date on the graphical calendar display. Click Apply then OK, the dialog box will close and the changes you made will take effect.
A failing CMOS battery can also result in incorrect computer time. This battery supplies minimal power to the motherboard so that BIOS can keep computer time synchronized even when the computer is turned off.