Open Chrome in the normal way.
With your left hand hold down the Control key (bottom left) and also the Shift key (just above Control) and then whilst doing that use your right hand to press the Delete key (top right on a laptop, to the right of Return on a keyboard).
A box headed "Clear browsing data" should open.
Against "Obliterate the following items from:" left-click the drop down arrow to select "the beginning of time"
Make sure that there is a tick against "Browsing history", "Download history", "Cookies and other site and plugin data" and "Cached images and files". (If not, left-click the box to its left to tick it.)
Ensure that the remaining items are not ticked.
Now left-click the button "Clear browsing data" at the bottom of the box.
When the box disappears close Chrome down and then reopen it.