Delete all your data

1. In the top-right corner of Chrome, click the Chrome menu
2. Select Delete browsing data.
3. In the BASIC dialog that appears, select the checkboxes for all of the following:

• Browsing history
• Cookies and other site data
• Cached images and files

MAKE SURE THE TIME RANGE to "All Time".  Then click CLEAR DATA.

It is also a good idea to reboot your device. Rebooting a chromebook is done by clicking on the sign-out box and clicking on the POWER icon and choosing shut down.