I would like to recommend Joomla plugin named Alarm System which added extra protection to Joomla Administrator/backend access.
With this plugin, you could enable the Alarm based PIN before access to your Joomla application.
Feel free to install Joomla Alarm System as URL below as it is free to use.
Recently, FBI found out that there are still 300,000 PC still infected with DNSChanger. If you are one of the victims, you might not able to access to the Internet or getting the similar site that you want to browse but with malware injected to the page that you visit.
To understand what is DNSChanger, please read the article from FBI at here.
To find if your PC is infected by DNSChanger, you might want to look at the instruction from the following URL,
With Malaysian user, you may used the following URL which operated by CyberSecurity Malaysia and MyCERT.