Features:

• All-in-one security for up to 3 Users from Microsoft protects personal and financial documents from the latest viruses, worms, hackers, spyware, and online identity scams
• Automate "janitorial tasks," including disk cleaning and defragmentation, to help improve PC performance
• Easily back up your files to a CD, DVD, external hard drive, locally networked computers, or most USB-connected storage devices
• Protect your PC from outside security threats while keeping things on the inside running smoothly
• Works with Microsoft Update to help ensure that your computer is up-to-date with the latest security and critical updates

Editor Reviews:

Product Description:
OneCare helps keep your PC safe and secure while making your life easier. From virus scanning, file backups, to automatic printing sharing of all the PCs in your household, OneCare helps manage it all for you. And it's delivered to you in a smooth, hassle-free package.
In one convenient package, Windows Live OneCare helps protect your computer, uses its optimization features to keep your PC running at its speediest, and even regularly backs up your important files: Protection Plus uses antivirus and antispyware scanners, a managed two-way firewall, and integrated anti-phishing technology to protect your computer from viruses, worms, Trojan horses, hackers, phishing, and other threats. It runs continuously, but you can scan individual files and folders for viruses on demand simply by right-clicking them. You can even scan attachments you receive via Windows Live Messenger or MSN Messenger.
Performance Plus regularly defragments your hard disk, removes any unnecessary files that may clog your computer, and helps ensure important security updates from Microsoft are installed efficiently and on time.
Backup and Restore regularly copies your important files and settings to CD, DVD, external hard disk, network drive, or other data-storage device. Instant Help provides online help anytime you need it, 24 hours a day, 7 days a week

Amazon.com:
Windows Live OneCare is the all-in-one PC security and performance service designed specifically for Windows XP and Windows Vista-based operating systems. It helps keep your PC's internal workings in order and protect it from outside security threats.

Protection for your files and information
Automatically helps protect personal and financial documents, music, photos, whatever you're saving--from the latest viruses, worms, hackers, spyware, and online identity scams.

Performance tune-ups
Automates "janitorial tasks," including disk cleaning and defragmentation, to help improve PC performance.

The all-in-one PC security and performance service designed specifically for Windows XP and Windows Vista-based operating systems.

Data back-up and restore
Makes it easy to back up your files to a CD, DVD, external hard drive, locally networked computers, or most USB-connected storage devices.

Your PC's Best Friend
OneCare helps protect your PC from outside security threats while keeping things on the inside running smoothly. OneCare includes:

• Antivirus and Antispyware
• Anti-Phishing
• Managed Firewall
• Data Backup and Restore
• Performance Tune-ups

All-in-One

All-in-one security service

• Virus and spyware protection helps shield your PC from contamination. Real-time scans identify and clean infected files and help protect your computer against pop-ups, slow performance, and security threats caused by spyware and other potentially unwanted software.
• Phishing filter in Internet Explorer 7 is activated to help detect and block known sites for online ID scams and theft.
• Firewall helps keep hackers out and private information in.

Boosts PC performance

• Tune-ups keep your PC running smoothly.
• Automatic disk cleanup, defragging, file backup and recovery on your schedule.
• Scheduled backups to CD, DVD, external hard drive, locally networked computers, or most USB-connected storage devices.
• Restores specific or all backed-up files.

One subscription

• Helps protect and maintain one, two, or three computers for one price for one year.

Automatic

Automatic protection

• Runs continuously behind the scenes while you're using your PC.
• Helps counteract new virus threats and block new harmful applications.

Automated PC tune-ups and maintenance

• Helps keep your PC running quickly and efficiently.

Automatic updates

• New feature and version upgrades included for as long as you keep your service active.
• Works with Microsoft Update to help ensure that your computer is up-to-date with the latest security and critical updates from Microsoft.

Simple

Task Bar Icon

• Always shows your PC's health status

  Green means your PC status is Good.

  Yellow means your PC status is Fair.

  Red means your PC is At Risk.

• One-click resolutions make it easy to take the necessary action to get and stay green.

Helpful

The OneCare Advantage:

• Unlimited, free Windows Live OneCare phone, email, and chat support.
• Automatic version and feature upgrades for as long as you keep your subscription active.
• Continuous technology improvement to combat emerging threats.
• Each OneCare subscription helps protect and maintain up to three Windows XP or Windows Vista-based PCs for one year.

Rating : - Don't waste your time installing on an older computer
I thought this would be worth a try since it came included with Qwest DSL service, and reviews here seemed generally positive. It did not work well on my 7-year old system, though. After a couple weeks struggling with it, I finally was able to uninstall it.

First of all, this requires a lot of RAM. My system was doing OK, but getting a bit low on RAM at 384 MB until I installed this. With Windows Live OneCare installed it wanted around 500 MB just to boot up--even while not running anything. So it was using Virtual Memory and paging like crazy, with the CPU pegged at 100%, even after I let it sit for hours, thinking it just needed to run an initial scan. Well, RAM is cheap and it was time, so I went ahead and upgraded to 1 GB (as much as my old motherboard can handle.) That was a lot better. Then the other annoyances began.

I run normally under a limited account, and WLOC was constantly bugging me to allow various processes to access the Internet, etc. To do so I'd have to log out and log in under an adminstrative account. The worst thing was just plugging in a USB flash drive would require an administrative installation--EVERY TIME. That got old in a hurry.

The last straw was it started interfering with proper shutdown of the system. Instead of shutting down, it would just hang. Then after all my other computers had automatically installed this week's critical MS Update, and this one still hadn't, I tried manually installing it by going to [...]. It just hung IE, and wouldn't even open the page. So I decided to uninstall it. Guess what? Control Panel Add/Remove Programs wouldn't come up. Windows Restore wouldn't work because it wouldn't shut down properly. Luckily I found OneCareCleanup.exe via Qwest's help center, and that did the trick. Now all seems well, and I've reinstalled the security software I previously was using.

Bottom line, I wasted a lot of time on this. Microsoft ought to do better. This is bloatware at its worst, as far as I can tell. Maybe it's better on a new machine, but I definitely do not recommend it on an older system.