The following steps is to lead you to system restore application.
Turn off computer > turn it back on > when it comes to sign in screen, left click at the Power icon which is at the bottom right corner > one of the options that pop up will be Restart > press SHIFT key and HOLD > click Restart > click Troubleshoot > click Advanced Options > click System Restore.
Click the option to choose another restore point >if you don't have the option to choose, just click Next > bottom left, check the box "Show more restore points " > now choose a date that is 2 to 3 days ago , click that date > click Next > follow the prompts from then on...............
When system restore is finished, it will reboot back to your desktop. See if everything is ok .