There are a million reasons for Windows to stop working from malware infection to Windows updates. When Windows is unable to boot and you have to access the internet to find ways to fix the problem, you can use a Live Linux CD like Puppy Linux. And if you want a Linux distribution that is specially designed to fix the system when it is having trouble booting up, then you can use the SystemRescueCd. It is a Linux based bootable CD that comes with a collection of tools using which you can fix your system problems.
SystemRescueCd will allow you to boot into your PC even when you are not able to boot into Windows. Through the use of this bootable CD, you can repair your system, recover important data and remove malware. It comes with all the necessary tools like GParted (for managing partitions), ClamAV (for removing virus infection), TestDisk(for recovering partitions), PhotoRec (for recovering media files such as pictures and videos), Chkrootkit (for removing rootkits), wipe (for shredding files securely) and many more. Since it is based on Gentoo Linux and contains several packages from the Gentoo distributions as well.
You can create both a bootable CD or a bootable USB disk containing SystemRescueCd. For the bootable CD, you simply have to download the ISO image file and burn it on a blank CD using a tool like ImgBurn. And if you want to create a bootable USB drive, then you can download the USB creator tool provided by SystemRescueCd developers themselves.
In this USB drive creator tool, you can select the downloaded ISO image and create a bootable USB flash drive from it. This tool also gives to opportunity to edit the contents and recreate the ISO. If you do not want to use the CD or USB drives for using SystemRescueCd, then you can also install it on your hard drive. When installed on the hard drive, it boots way faster and works much smoother than when booted from a CD or USB drive.
You can download SystemRescueCd from http://www.system-rescue-cd.org/.