Windows XP A to Z - http://www.softwaretipsandtricks.com/windowsxp
Change Internet Time Update Interval
http://www.softwaretipsandtricks.com/windowsxp/articles/208/1/Change-Internet-Time-Update-Interval
Super Admin
 
By Super Admin
Published on 02/23/2005
 
To change the interval that Windows updates the time using the internet time servers
Change Internet Time Update Interval

Navigate to:

1. HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\W32Time\Tim eProviders\NtpClient

2. Select "SpecialPollInterval"

3. Change decimal value from 604800 to some other
   value in seconds. EX: 172800 (2 days)