If you for some reason can't access the following sites: mail.ru, odnoklassniki.ru, vkontakte.ru, vk.com then you have to change, or rather clear, the file host. Click on "My computer" by pressing simultaneously the keys "start" and E.
Now open the list of folders located on the system partition of the hard drive. Navigate to the Windows directory. Now find and open the System32 folder. Navigate to the Drivers folder and open the etc folder. Find a file host that has no extension. Click right mouse button and select "Open with".
Now select Notepad and click OK. Delete all the contents of this fileby pressing Ctrl and A and then Delete. Save by pressing Ctrl and S. to Close it. If the message that you do not have access rights to this file, then close the host file without saving. Click again the right mouse button and select "Run as Administrator". Repeat the algorithm described above.
If so, you failed to flush the contents of this file, just delete it. In the case where the deletion of the file cannot host, restart the computer and hold the F8 key. In the menu that appears select "Windows Safe mode". Follow the procedure of cleaning the desired file as described in the third step.
If you cleaned the host file and access to resources did not appear, repeat the algorithm entry in the etc folder. Now open the folder and go to the tab "View". Check the box next to "Show hidden files and folders". If after activating this item, you see another file host, do the cleaning. Be sure to check your computer's antivirus program after performing all the above procedures.