From MEPIS Documentation Wiki
It is a very good idea to be prepared for the worst, like total hard drive failure or pressing the Apply or Delete button at the wrong time and consigning many years' worth of data into oblivion. You can do this by making yourself an emergency System Repair Kit before disaster strikes. Here are the essential elements:
1) MEPIS Installation CD (aka LiveCD) -- Keep this handy. It contains various options to be able to REPAIR the installed MEPIS on the hard-drive, including ( but not limited to): repairing the grub/boot info, using its GParted to make disk-partitioning changes, and mounting any disk-partition and then editing any files, etc. Make sure you first login to the LiveCD as 'root', and use password 'root', and then you're good to go to use any repair feature. If you need more detailed help on these techniques, just search/ask in the MEPIS Community forum.
2) SystemRescueCd -- Absolutely essential, the ultimate PC rescue system and capable of restoring most dead PCs to life again, or at least capturing their lost data. It is a good idea to print a copy of the Quickstart Guide and List of System Contents.
4) Knoppix Live DVD is a huge 4.4GB affair containing lots of useful repair tools.
5) G4l CD -- A superb tool to clone one drive, or partition, to another.
6) Your backup disk. At a MINIMUM, you should backup stuff from your '/home' area (or partition, if you have that). The root-partition ('/') is easier to just re-install MEPIS into (especially if you created '/home' as a separate partition during installation). You can either backup selected portions (key files) from the root-partition, or backup/restore the entire root-partition. As long as your hard-drive(s) aren't damaged, you could use the LiveCD to recover selected files from any/all partitions (e.g. copy them out onto a USB-flash-drive, etc). [Click the 'backup' word at beginning of this paragraph for more info.]