First try this: on the top tool bar, there is a refresh button, it is two green arrows, forming a circle, click that. If that doesn't work....
Are you on windows? Look at your lower left hand corner, do you see green box with a microsoft logo and word start in white?
Click that, a box should come up. On the right side click on control panel. The control panel will pop up. Click on network and internet connection, that will open. Top left icon in the bottom section should say inernet options, click that. Another window will pop up. The middle section says temporary internet files..click delete cookies. Bottom section is History, hit clear history.
Now close all your windows. Hit the green start button again, in the lower right will be a botton that says turn off computer, hit that. A new window will pop up, click the far right button that says restart. If can take a few minutes, so don't get nervous, just let it do it's thing.
Good luck