In a perfect world, you wouldn't be concerned about safety when you use your computer. Short of that, you just want to feel confident your PC is virus-free, protected from the prospect of future infections, and easy to recover if something goes wrong. Three things that will help ease your mind are a manual malware scan, an easy-to-restore copy of your hard drive, and a sandbox for your browser to run in.
Run your system through a second-opinion virus scanner
Even the best real-time antivirus scanners miss a small percentage of malware. A second scan with a different virus catcher improves the likelihood that your system is clean. The free Malwarebytes Anti-Malware is on my short list of must-have programs.
Before you run a scan, Malwarebytes updates its virus database. A full scan of a laptop with a 500GB hard drive took one hour and 17 minutes. The scan identified four adware and two spyware entries in the 384,000-odd objects it processed. When the scan completes you're prompted to restart the system to remove the malicious entries.
Whenever Malwarebytes IDs suspicious files, I rescan until the results indicate no potential malware. Just in case, I check for alerts in the Windows Security Center to make sure the Windows firewall, virus and spyware scanners, and other security options are active. With a clean bill of health, the drive is ready to be imaged.
Put a full backup of your hard drive on a removable medium
If you rely on your computer for your livelihood, you need two very different backup approaches. The first stores relatively current backup copies of your important files somewhere other than the hard drive. The second is an occasional cover-to-cover backup of the PC's hard drive, whether onto DVDs or to an external hard drive (some people still swear by tape drives).
The convenient approach to the first type of backup--frequent offsite backup of individual files--is use of an online storage service. In April I described the free Google Cloud Connect add-on for Microsoft Word, Excel, and PowerPoint. Cloud Connect automatically syncs files in the three Office apps with the free Google Docs Web service.
Another option is the DropBox service, which is free for up to 2GB of storage. DropBox lets you upload files for storage and sharing by dragging them into a folder the program creates in Windows Explorer; I described the service in a post earlier today.
I'm embarrassed to admit that the image backup of my notebook PC's hard drive is now more than a year old. It's time for me to crank up the free Easeus Todo Backup utility, which I wrote about in March 2010.
Several user reviews on the program's Download.com page indicate Easeus Todo Backup doesn't work well for everyone. If you use Windows 7 or a version of Vista other than Home Premium, you can use the disk-imaging utility built into Windows. Open the Backup and Restore Control Panel applet and click "Create a system image" in the left pane. Then step through the wizard, selecting the device you'll use to store the backup.
Once the image is created, start the restoration process to ensure the backup is recoverable. This includes making sure your PC will boot from whichever device you used to store the image. How you create the full backup is less important than having a somewhat-current full backup you know you can recover.
Some people may think Windows' System Restore feature is all the PC insurance they need. While System Restore can be a real behind-saver, the feature isn't completely trustworthy. For any number of reasons you may find yourself with no restore points available when you need one most.
Confine your browser in a no-changes-allowed sandbox
The best way to inoculate your system is by browsing in an environment that prevents any program from permanently altering your settings. Last August I described the free Sandboxie program that lets you open your browser, e-mail app, or other program in a virtual environment, which is a kind of safe mode.
To activate a sandbox, select the Sandboxie shortcut on the Start menu and click either "Run any program sandboxed," "Run Web browser sandboxed," or "Run Windows Explorer sandboxed." Choosing the browser option opens your default browser in a walled-off environment.
Nothing that happens in the sandboxed environment takes permanent effect. After you close the sandboxed programs, open the Sandboxie Control window by double-clicking the utility's icon in the notification area. Then choose the sandbox on the Sandbox menu, and click Delete Contents.
Sandboxie and other virtual-environment programs don't alert you to the presence of malware, but they add a layer of protection that further isolates you and your data from the prying eyes of Internet thieves. In conjunction with regular full malware scans and disk-image backups, sandboxes help you spend more time working and less time trying to recover from some computer misfortune.