Alert levels in Microsoft Security Essentials

When Microsoft Security Essentials detects a potential threat, it uses the associated definition file to assign an
alert level to the threat. It then applies the default action associated with that threat level.

Alert levels help you choose how to respond to viruses, spyware, and other potentially unwanted software.
While Microsoft Security Essentials recommends that you remove all viruses and spyware, not all software
that is flagged is malicious or unwanted. The information in this table can help you decide what to do
if Microsoft Security Essentials detects potentially unwanted software on your PC.

1.Alert level :Severe

What it means :These are widespread or exceptionally malicious programs, similar to viruses

or worms, which negatively affect your privacy and the security of your PC, 

and can damage your PC.

What to do :If you're prompted, remove the detected software immediately. Unless you've 

changed the default settings, Microsoft Security Essentials will attempt to remove malicious 

software automatically, helping protect your computer from potential infection. 

(After automatically removing malicious software, Microsoft Security Essentials might 

also reset some Windows settings, such as your default home page and search provider.)

2.Alert level  : High

What it means  : These are programs that might collect personal information and negatively 

affect your privacy or damage your PC. For example, the program collects information 

or changes settings, typically without your knowledge or consent.

What to do : If you're prompted, remove the detected software immediately. Unless you've 

changed the default settings, Microsoft Security Essentials will attempt to remove malicious 

software automatically, helping protect your computer from potential infection. 

(After automatically removing malicious software, Microsoft Security Essentials might

 also reset some Windows settings, such as your default home page and search provider.)

3.Alert level  : Medium

What it means  : These are programs that might affect your privacy or make changes to your 

PC that could negatively impact your computing experience. For example, the program 

collects personal information or changes settings.

Review the alert details to see why the software was detected. If you don't like what the 

software does or if you don't recognize and trust the publisher, consider blocking or removing 

the software.

4.Alert level  Low

What it means  : This is potentially unwanted software that might collect information about 

you or your PC or it might change how your computer works. However, the software 

is operating in agreement with the Microsoft Software License Terms displayed when 

you installed the software.

What to do : This software is typically benign when it runs on your PC, unless it was installed 

without your knowledge. If you're not sure whether to allow it, review the alert details, 

or check to see if you recognize and trust the software publisher.

by : http://windows.microsoft.com/