It is designed to scare or fool the victim into purchasing it.
Personal Shield Pro is installed on the computer through the use of trojans that pretend to be updates to various programs such as Flash, Shockwave, or codecs required to view an online video. This rogue is also installed by exploiting vulnerabilities in programs installed on the computer when visiting sites that have been hacked with exploit kits.
After infecting the computer Personal Shield Pro will start automatically when Windows boots and perform a fake scan that states that the computer is infected with malware.
Personal Shield Pro will also terminate most programs that attempt to run while stating that the program is infected.