The current time on this computer and the current time on the network are different. For more information about Date/Time Properties, see Help and Support. To log on, contact your system administrator.

PROBLEM

When you try to logon in to Windows XP that is joined to a network you get the following error:

The current time on this computer and the current time on the network are different.  For more information about Date/Time Properties, see Help and Support.  To log on, contact your system administrator.

CAUSE

This can be casued by a few things, either the user changed the time or the date in the machine.
A firewall is blokcing the communication between the workstation and the server to Sync the time
The Windows Time Service is Stopped
The workstation is no longer in the network where it belong and is looking for the server to Sync
The BIOS battery died and all date related got changed

SOLUTION

1. Be sure the Windows Time service is running:
    a. Click on START>RUN
    b. Type services.msc
    c. Look in the list for Windows Time and confirm it says "Started", if not right click and select "Start"

2. Logon as administrator
3. Click on START>RUN
4. Type cmd
5. In the black screen type net time /set
6. The computer will show the follwowing message:

Current time at \\YOUR_SERVER_NAME is mm/dd/yyy TT:TT PM or AM
The current local clock is mm/dd/yyy TT:TT PM or AM
do you want to set the local computer's time to match the time at \\YOUR_SERVER_NAME? (Y/N) [Y]:

7. You can type "Y" for Yes or "N" for No
8. Now both time on the local computer and the server should be the same