Microsoft has released an easy-to-use bootable malware removal tool called Standalone System Sweeper. This makes the once complicated process of using a bootable virus scanner simple enough for even the technically inclined to handle. If you have a virus infection that simply won’t go away, give System Sweeper a try!
At it’s core, Standalone System Sweeper is simply Microsoft Security Essentials wrapped in a bootable environment. You can download it on a working computer, and it will walk you through the process of burning a CD, DVD or preparing a USB drive. I would recommend using a blank CD or DVD, since USB drives can be difficult or impossible to boot to on some older machines.
Once you have your CD or DVD burned, put it in the infected computer and boot to it. Usually this will happen automatically when you restart the computer with the disc in, but sometimes you’ll have to press a key (most commonly F12) right when the computer is first starting to boot up. You’ll then see the bootable Windows environment start to load. This boot process will probably look similar to what you would see if you were booting a normal Windows 7 machine. However, there’s actually a full (but slimmed down) copy of Windows 7 on that disc which System Sweeper will run on. Your infected hard drive isn’t being used to run the computer at all at this point. This way, the virus that was previously stopping you from running virus scans or opening programs will have absolutely no chance to start running and getting in the way.
Once System Sweeper starts, you’ll be able to update the virus definitions (under the Help dropdown menu) and run a full scan of your hard drive. Again, this is basically the same Microsoft Security Essentials virus scanner running, but this time it’s running in a clean environment without any active viruses to get in it’s way. After the scan, you can click “Clean Computer” to have System Sweeper clean all of the infections it found on your hard drive.
And that should be it! Take the disc out, restart your computer and you should boot back into your normal copy of Windows with everything nice and clean. You might notice some strange files or settings left over from the infection, but there shouldn’t be anything major stopping you from cleaning those up manually or with other virus scanners now. Bootable anti-virus for the people!