How to remove Yandex bar from Google Chrome:

1. Click on the 3 horizontal lines icon on the browser toolbar;
2. Select Settings;
3. Select Basics ->Manage Search engines;
4. Remove unnecessary search engines from the list;
5. Go back to Settings. ...
6. If your New Tab page is hijacked, you will have to scan with anti-malware program or use New Tab Redirect extension from Chrome Store.

Remove yandex.com from websites, allowed to show push-notifications in Mozilla Firefox

1. Go to Mozilla Firefox options, by clicking 3-bars icon in the top-right corner and choosing Options.
2. Choose Content tab on the left side.
3. Under Notifications, set up preferred overall settings for push-notifications and click Choose… button.
4. Find yandex.com in the list and click Remove site to remove it.
5. Click Save Changes button to confirm the action.