- Anti-Virus/Anti-Spyware. Microsoft Security Essentials is an effective tool based on what of seen and read, as well as my own experience. I was a subscriber to Windows Live OneCare which handled Virus Protection, Spyware, Operating System patches and backups in one easy to use application. Unfortunately Microsoft discontinued this little gem and offered Security Essentials in its place for free.
- Backups. The simplest and easiest backup application is built right into your Microsoft operating system. I'm running Windows 7 Backup & Restore but the Windows XP OS has a similar feature. I use an external drive to store the backups. The great thing about these backups is how easy it is to restore multiple user profiles when rebuilding my PC from scratch (i.e., reinstalling the Operating System).
- Application Update Notifications. I've been using this great free product for several weeks now, FileHippo Update Checker. It's free and it has been working well without any problems. In the four weeks or so since we've installed it I've been notified of at least six different software application updates including the Sun Java Runtime, Apple iTunes, Apple QuickTime, Adobe Reader, Adobe Flash, Google Chrome, and more.
- Operating System Patches. Once again, built right into the Windows operating system is Windows Update. I've been using this for years now without a problem. In addition to Operating system updates, Microsoft Office updates are included as well.
Popular Anti-Spyware options include Spybot S&D, Ad-Aware (free version), and Windows Defender.
LifeHacker.com has an excellent guide to keeping your PC up to date...