Beware - Desktop Hijacks on the Rise Again
from http://www.dslreports.com/faq/14427
Security Forums have been deluged with daily cries of help from victims
of the "Smitfraud" desktop hijackers that are using fake codec to infect
their prey.

Watch out for the Zlob Trojan that poses as a codec needed to view a
video, then installs a fake virus and urges its victims to download a
rogue anti-spyware program to remove it. Lavasoft has also confirmed
that this malware takes advantage of unpatched systems using exploits on
web pages*. Visit Microsoft Update* to ensure that ALL of your critical
Windows security pages are updated. Dont click on any links in emails,
unless you have verified by other means that it was sent by the known
sender. Unknown are taboo in all cases.

Other victims have been infected by a fake e-card greeting, or even a
spoofed e-mail that claims to be Windows Update (Microsoft never sends
updates via e-mail). Still more unassuming victims received an e-mail
asking them to open a link to see the message (these can be fake
e-mails, intended only to infect), or even a link from your 'buddy' in
instant messages - *but don't trust it if you aren't expecting it*. Even
your buddy could be infected without his/her knowledge and the virus on
their computer is sending you the link with one purpose, and one purpose
only - to infect you!