How to Backdate a Computer
Backdating a computer is a common practice for one reason or another. It is a simple procedure.
Click on the clock on your taskbar. It is located at the bottom right corner of your screen.
Click on the link "Change date and time settings" if you are using Windows Vista or higher.
Click on the button that says "Change date and time." You will find this button under the tab "Date and Time."
Ignore Steps 2 and 3 if you are using Windows XP or lower.
Choose a date and time by clicking on the little up and down arrows next on the calendar and the clock.
Click on "Apply" and hit OK to complete the task.