In Windows Server 2012 R1/2, 2008 R1/2, 7, Vista, and 2003 SP2 and later, whenever time is out of sync, it’s good to run the following two commands in an administrative command prompt (an ordinary command prompt for 2003SP2+):

w32tm /config "/manualpeerlist:north-america.pool.ntp.org 0.north-america.pool.ntp.org 1.north-america.pool.ntp.org 2.north-america.pool.ntp.org" /syncfromflags:MANUAL /update 
w32tm /resync

If the service has not been registered, the whole canole is:

w32tm /register
net start w32time
w32tm /config "/manualpeerlist:north-america.pool.ntp.org 0.north-america.pool.ntp.org 1.north-america.pool.ntp.org 2.north-america.pool.ntp.org" /syncfromflags:MANUAL /update 
w32tm /resync

Under Windows 2000, we need to go a bit more archaic:

net time /setsntp:north-america.pool.ntp.org
net time /querysntp

Two addenda:

• We used to recommend just pool.ntp.org , but geoblocking has become quite common, so a more geographically appropriate setup is now the rule.
• Do the above for domain controllers, standalone PCs, and mobile laptops. Add the domain controller’s IP to “Time Server” in DHCP, to reach desktops.