The time zone names, offsets, and begin/end rules for summer time are stored in the system registry, in the path HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\\Time Zones The keys under that path are the time zone names; within each key are the values Display (the name to display in the Control Panel) Std (the name to use for standard time), Dlt (the name to use for summer time), Index (a number of the zone, but not terribly useful), MapID (a map location of the zone, again not useful since that functionality was removed from the Control Panel), and TZI. The TZI value is an encoded version of a TIME_ZONE_INFORMATION structure. http://msdn.microsoft.com/library/en-us/sysinfo/base/time_zone_information_s... The two WCHAR arrays are removed, so there are - bias (minutes west) - 32 bits - standard bias (adjustment as of 0 January) - 32 bits - daylight bias (adjustment in Northern summer) - 32 bits - the fields of the two SYSTEMTIME structures, in order. -- 73 de ke9tv/2, Kevin KENNY GE Corporate Research & Development kennykb@crd.ge.com P. O. Box 8, Bldg. K-1, Rm. 5B36A Schenectady, New York 12301-0008 USA