Microsoft have released what appears to be a successor to Windows Defender, a revamped Windows Live OneCare with greater functionality. Microsoft Security Essentials is available to download for Windows XP and Windows Vista/7 32/64 bit editions, and provides Real Time virus scanning as well as Anti-Spyware protection. Upon installation (which validates the Windows OS), Windows Defender is deactivated (but can be turned on later if necessary) and MSE begins updating and scanning. I advise not using both MSE and Windows Defender together since two Real Time systems may conflict and result in false negatives.

Overall, the performance of MSE after a day of usage is very lightweight in terms of RAM usage, and the interface couldn't be simpler. Tests have shown reliable and sometimes more effective file treatment than products such as Symantec's Norton. I recommend the switch to MSE for users of other free antivirus software which have paid versions, such as AVG.

Alex Kara