Newbie question - How to install PSM

[user]

Hello!

I apologize in advance if my question is not approriate here. I have 
just tried to enter a website and I received this notice," This document 
 cannot be displayed unless you install the Personal Security Manager 
(PSM). Download and install PSM and try again, or contact your system 
administrator." My question is, where can I get PSM and install it on my 
computer?

Thanks!

Thaitv