Wow, great, [CTRL]+[ALT]+[SHIFT]+[L] saved the day. Lost directories and mails are back. Thank You, hundred of times thank You.
Please tell one more thing. This upgrade to the latest 4.0 version, is it just upgrade, and all setups and mails will stay intacted, or i need to do backup, and then to do completely new fresh instalation, and then restore mails and rest?