Microsoft Security Essentials - MSE

Microsoft Security Essentials (MSE) represents Microsoft's free anti-malware solution for computers running XP, Windows 7 or Vista. It's considered by most third-party developers and testers to be a "baseline" among av products, and Microsoft never stated the contrary.
In order to get updates for XP, don't forget to apply the XP registry patch.

App installation and interface

Installing MSE is fast and easy. Its only requirement is that no other antivirus applications exist on the PC since they are most likely to clash and cause Windows stability issues. Right before completing setup, the tool offers to run an initial scan to assess the PC's current security status as soon as it fetches the latest virus definitions.
As far as the interface is concerned, MSE keeps separated the areas for scanning, virus, and spyware definition updates, history, and settings. The overall look is comfortable and neatly organized, so inexperienced users shouldn't experience any issues in navigating it.

Scanning modes and configuration

There are three scanning modes available: "Quick" verifies only important system areas like Program Files and the Windows directory, "Full" runs a complete checkup on the computer, while "Custom" enables users to select the exact drives and directories to look into for malware (also possible via contextual scanning). Quick and full scan jobs can be scheduled to run on a regular basis.
When it comes to modifying scan settings, users may establish default actions for threat detections, depending on the alert level (low, medium, high, severe). The real-time protection module can be disabled, while custom files, folders, file types, and processes can be excluded. Other scan options focus on archives, removable drives, system restore points and quarantined files. Furthermore, it is possible to inspect and keep or delete quarantined files.

Evaluation and conclusion

MSE has a very good virus detection ratio and generally uses low CPU and RAM. However, it is quite slow regarding scanning speed, while software notifications cannot be disabled or controlled. Although Microsoft Security Essentials is not among the most powerful av products out there, it serves as a pretty good startup tool for casual users. Upgrading to a more powerful tool is a step necessary to take, though, sooner or later.
Microsoft Security Essentials - MSE is part of these download collections: Scan For Viruses, Free Antivirus, Remove ZBot, Detect Malware