Malware writers use every trick in the book when it comes to social engineering schemes. AntiVirus 2009 employs some convincing graphical displays to trick users into thinking they are infected and to install this product for cleaning. It appears to be spreading through email, IM, and social networking websites. New variants are also constantly emerging in these spam runs to avoid AV detection.
If any infection is found, users are much better served installing a true mainstream AV solution instead. In addition, to full feature AV products, there are even good free alternatives, that can do a good job in basic prevention or cleaning. As a golden rule, never install any type of software from an email link. In fact, it's always beneficial in avoiding taking ANY actions on most email messages you receive.
QUOTE: Researchers at TrendLabs have discovered a new set of rogue antivirus software circulating in the wild. Based on initial analysis, these threats arrive mainly via spammed email messages that contain a link to a bogus celebrity video scandal, although we have also received reports that the said link is also circulating in instant messaging applications and private messages in social networking Web sites.
RENOS Trojans are known to have very visual payloads that may further alarm users (for example, they modify the system’s wallpaper and screensaver settings to display BSOD). Thus, users may be more convinced that something’s wrong with their system, not knowing that their new software is the one causing it.