Bravo for Microsoft!  This month’s release of the Malicious Software Removal Tool removes rogue antivirus (like XP Antivirus 2009) and fake system alerts (like “you have a security problem” or “Your computer is at risk”).

In the first week alone the MSRT removed over 900,000 rogues in the US!  Here is an excerpt from the MS Malware Protection Center

Also Known As:
Win-Trojan/Downloader.56320.M (AhnLab)
Win32/Adware.XPAntivirus (ESET)
not-a-virus:Downloader.Win32XpAntivirus.b (Kaspersky)
FakeAlert-AB.dldr (McAfee)
W32/DLoader.FKAI (Norman)
Mal/Generic-A (Sophos)
XPAntivirus (Sunbelt Software)
Downloader.MisleadApp (Symantec)
XP Antivirus (other)
Antivirus 2009 (other)
Summary
Trojan:Win32/FakeXPA is a family of programs that claim to scan for malware and display fake warnings of “malicious programs and viruses”. They then inform the user that they need to pay money to register the software in order to remove these non-existent threats.

Special Note:
Reports of rogue Antivirus programs have been more prevalent as of late.  These are programs that generate misleading alerts and false detections in order to convince users to purchase illegitimate security software.  Some of these programs, such as Trojan:Win32/Antivirusxp and Program:Win32/FakeRednefed may display product names or logos in an apparently unlawful attempt to impersonate Microsoft products.  These products may represent themselves as “Antivirus XP”, “AntivirusXP 2008”, “WinDefender 2008”, “XP Antivirus”, or similar.

Use Microsoft Windows Defender, the Windows Live safety scanner (http://onecare.live.com/site/en-us/default.htm), or another up-to-date scanning and removal tool to detect and remove these threats and other unwanted software from your computer. For more information on Microsoft security products, see http://www.microsoft.com/protect/products/computer/default.mspx.