Your clock is behind
When you have a "Your clock is behind" message on the screen, it means that your computer's date and time are not correct. If you're not sure how to change them, here's a quick guide to fix your clock is behind error:
Windows 7 / 8 / 8.1:
Click on the Start Menu
Type "clock" in the search box and select "Change the date and time settings"
Click on the "Internet Time" tab
Make sure that the box next to "Synchronize with an Internet time server" is checked
Select a time server from the drop-down list
Click on "Update now" and then click on OK three times to confirm your changes.












