A lot of the top antivirus providers offer a free bootable recovery disk for disinfecting your computer following an infection. These are tools based on Linux that can be used to clean the computer of malware if it’s not able to start up or isn’t scanned by the standard antivirus program running on Windows. I recommend the Kaspersky disc for its ease of use (though it might not work with certain Dell systems).
You can also access similar features using the Avira or ESET rescue disks, which have visual interfaces but require the use of a USB/CD device to boot. Both options can scan and decipher any malware that is present on your computer. However their virus definitions may not be constantly updated like the Linux-based Rescue Disks.
The Trend Micro rescue disk is another option and one of the smallest options on this list with around 70MB. It doesn’t come with a graphic user interface but it works quickly and offers a few customization options including the capability to mount and scan specific drives, files and even individual folders.
The Comodo Rescue Disk is a good option to run a virus scanner, although it does not have the same flexibility as the alternatives that run on Linux. It is however a very efficient tool to detect and eliminate viruses that can hide themselves in Windows files to thwart detection by antivirus programs that are normally used. You can choose to use an interface that is text-only or a full-graphic interface. You can also conduct a smart scan or a custom scan.