Same song, different pew this time. Sandi Hardmeier reported that MSN Messenger banner advertisements were distributing Winfixer. It was reported to firstname.lastname@example.org and it is being actively investigated by them and MSN ads team. As of now, the three featured advertisements seem to be gone, although Sandi is still in touch with those behind email@example.com and should have more to report tomorrow.
This is extremely disturbing. However, rather than repeat what Sandi wrote about the problem, its best for you to read it first hand in WARNING: Winfixer and Errorsafe being distributed via MSN Messenger banner advertisements. DiggIt here.
What I will repeat here is Sandi's strong admonition if you feel you still have to use MSN Messenger:
"I strongly recommend that all users of MSN Messenger ensure that their antivirus and antispyware applications are up to date. Do not click on any buttons in pop-up windows that you may see, and do not believe Web sites that report that they have found a problem on your computer - seriously, how the hell would they be able to tell?
Do not click on OK or Cancel buttons in the pop-up windows. Close the window using the red x close button.
I also strongly recommend that MSN Messenger users download and install Mike Burgess's HOSTS file to help block winfixer and other bad guys. You can find Mike's famous HOSTS file here: http://www.mvps.org/winhelp2002/hosts.htm"