Dear professionals please help me.

I've been using 1.8.2 "Toliara" multilingual version about 2 years without any problem.
A few days ago when I requested my site I got the following message:
--------------------------------------------------------
The Website Ahead Contains Malware!
Google Chrome has blocked access to lexbox.am for now.
Even if you have visited this website safely in the past, visiting it now is very likely to infect your Mac with malware.
Malware is malicious software that causes things like identity theft, financial loss, and permanent file deletion.
----------------------------------------------------------

1.8.2 was released in August 2010. Lots of updates, bug fixes and vulnerability corrections since then. You'll probably want to upgrade the site to the latest version, currently 1.11.4.

Take a look here for instructions:
http://docs.cmsmadesimple.org/upgrading

don't forget to check the content of the site for strange code.