SystemRescue
A Linux system rescue toolkit as a bootable removable device
... and windows computers, and on desktops as well as servers.
This rescue system requires no installation as it can be booted from a CD/DVD drive, and USB stick, or from the network using PXE. But it can be installed on the hard disk if you wish. It comes with up to date kernels to provide support for recent hardware and also for all important file systems (ext2/ext3/ext4, xfs, btrfs, ntfs, reiserfs, vfat), as well as network filesystems (samba and nfs).