If Windows 8 has been installed on a 2go pc, and the error message "Boot Certificate Expired" is displaying when the unit is powered on, follow these steps in order to resolve the issue (Note: This procedure will only be successful with Windows installation media, if no media is available, then follow this link: http://ctl.helpserve.com/Knowledgebase/Article/View/290/4/how-to-request-a-repair-of-a-2go-pc):
At the error screen, press Ctrl + Insert to enter the BIOS menu.
Change the system date to the year 2000, then Exit and Save changes.
If using a Windows CD, insert the disc when the unit restarts and follow the prompts to re-install the alternate operating system (a restart may be needed after inserting the disc).
If using a USB media device,press F11 (or appropriate function key) to enter the boot menu when the unit restarts.
Select the appropriate boot device from the selection menu, and install the alternate operating system.