I have reset the password and after that the server has rebooted.
The Droplet [instance is active] however its not accessible from public network. we can see the server login page in VNC console. How can we do that? why server is not available on public IP? Nor do my website and admin is woking for this domain.
Try restarting the network from within
Root > service network restart
Confirm that the public IP has not changed. Are you able to ping to it externally ?
Try restarting the SSHD service for once if you are facing trouble to SSH to the instance.
Root > service sshd restart
Nor do my website and admin is woking for this domain.
Probably your webserver is no longer running ?
Root > service httpd restart or
Root > service apache2 restart
*Assuming Apache as your default webserver.
Hope it helps :)