Upgrade Issue - Upgrade 4.3.4 - 4.3.5

I recently upgraded my software about 3 versions prior to this one. Now when i click the upgrade center it gives me this option to upgrade

Upgrade 4.3.4 - 4.3.5

when i click it , the screen goes to the main dash board and it doesn't allow me to do anything else. I have to refresh the dash board to see the menu. I also can't edit settings. my store is currently closed and i cant re open it. it wont load anything i click.

what could be the issue ?

when i try to click on something in the back end it wont allow me to click. it wont go if its an action. Is this fixable or do i have to reload the back up?

At first try to delete the var/cache directory. If it does not help, please contact CS-Cart support team