Free, Linux-based operating systems can be downloaded and burn to a CD-Rom or DVD. If you want to run a rescue CD on a laptop, youll need to plug the notebook into a router or other Internet connection via a networking cable. Several anti-virus vendors offer burnable rescue CDs that are based on Linux, including AVG Rescue and BitDefender Rescue. You can use the CD to scan your hard drive and copy files to a removable drive.”]
Source: https://krebsonsecurity.com/2010/03/removing-viruses-from-a-pc-that-wont-boot/