I can´t open a demo account; MetaTrader shows blank password and login fields.

1. Perhaps in your network the port 443 is blocked and a proxy-server is used to connect to internet. If you use the working network of an organization most probably this is the very problem. You should ask your system administrator for the proxy-server address and the port to connect to internet and write them in the terminal settings (menu «Tools» / «Options» / «Server» / put a mark against «allow proxy-server» / click the button «proxy...» / write in the proxy-server address and port, login and password);

2. At your computer the program-firewall (antivirus software) blocks the 443 port. In such case you should include MetaTrader on the list of permitted programs or open the port 443.