When you deploy a Windows XP Sysprep.exe image, the BIOS RTC (Real Time Clock) on the client computer is set back one hour.
NOTE: This behavior will NOT occur if the BIOS stores time zone or daylight saving information.
This behavior will occur if any of the following is true:
• When the System Preparation image comes up, the operating system assumes the RTC is for the time zone that it is configured to use, but it wasn't.
• The computer was off before the Daylight / Standard time boundary was reached.
• If the image was created for DST with automatic daylight savings time adjustment, and the computer first starts in standard time.
• You dual-boot and both operating systems adjust the clock.
To workaround this issue, either create a new System Preparation image, or make sure that all operating systems are using the correct time zone and time and daylight settings.