Hands on: Microsoft Security Essentials review

Updated: read our full Microsoft Security Essentials review.

Late last year Microsoft announced that it would be shutting down its OneCare all-in-one computer protection service. OneCare's subscription was going to be replaced by a free download in the shape of a new anti-virus product codenamed Morro.

A few screenshots leaked, followed by the announcement of a beta program and the release of the final name: Microsoft Security Essentials. The beta's now available, and ready for download.

Microsoft Security Essentials is available for Windows XP (ideal for quickly securing Windows 7's XP mode), Windows Vista and Windows 7. It's a relatively small download, coming in at just under 5MB.

Installation is quick and easy, though there's a long wait while it downloads the latest antivirus and anti-spyware definitions, coming in on our test Windows 7 PC at a hefty 30MB of extra data.

FAMILIAR LOOK: Security Essentials looks very like its predecessors, OneCare and Windows Defender

UPDATES: The first definition download can take some time - so make a cup of tea

Once that's done, Security Essentials will run a quick scan of your system - and also start offering real time protection. A quick scan on a heavily loaded PC took around 10 minutes.

The default is to run a Quick Scan at 2.00 AM on Sunday morning. That's an unusual choice by Microsoft in these green days, as it's probably the most likely time for home and office PCs to be shut down. You'll need to make sure that the latest definitions are downloaded before each scan, as well as excluding specific files and locations, and certain file types.

SCAN: Scanning for viruses and other malware for the first time with Security Essentials - time to drink that tea

UP LATE: 2am? On a Sunday? It's well worth changing the default scan settings if you want a secure PC

Advanced options allow you to manage access to archive files and removable drives, as well as using system restore points any time Security Essentials deletes or quarantines files - especially useful if a false positive has affected your PC and you need to quickly get back to normal.

The default actions for an alert are all set to "Microsoft Security Essentials' recommended action", with no description of just what those are. There is a link to an online help page, but it's not much help, with much of the documentation still missing. For Severe and High alerts, the options are Remove and Quarantine, while Medium and Low alerts add the option to Allow.

DEFAULT ACTIONS: Just what are those recommended actions? Time for a security mystery tour!

Microsoft Security Essentials isn't just anti-virus software, it's also anti-spyware, and replaces Windows Defender. You'll still be part of the SpyNet network - Microsoft's distributed honeypot. SpyNet takes automated infection reports from compromised machines, and uses them to create improved definitions and signatures that can then be sent out to other machines running Security Essentials (and to businesses using Microsoft's high-end Forefront security products). It's a similar approach to that taken by CheckPoint with ZoneAlarm.

While the main web page indicates that the beta is only available to users in the US, Brazil, China and Israel, it is possible for UK users to get access through Microsoft's Connect beta service. Microsoft has said it will cap the beta at 75,000 downloads - so fire up your browser to give it a try. If you can't get onto the beta, the final version is due by the end of the year.