Windows 7, 8, and Vista - Changing the System Date and Time
This document explains how to change the system date and time in Windows 7, 8, and Vista.
Right-click on the time in the bottom-right of the screen and select Adjust Date/Time.
Click on the Change date and time... button.
Use the arrows to the left and right of the month/year and the arrows to the right of the clock to change the time to the correct time.