If you have a computer with a floppy drive, you can create a set of Boot Floppies and use them to boot the CD. The floppies can be made from Windows or Linux. The floppy images are on the SimplyMEPIS CD in the /floppies directory. You will need 3 floppy disks. In Windows, go to the /floppies folder on the CD and run mkflop.bat then insert the floppies when prompted. In Linux, as root, run mkflop.sh
To boot from floppy, insert both the Boot Floppy #1 and the CD, then reboot your system. From the floppy's menu, select to boot from CD for the version of MEPIS you are booting, and follow the instructions.
If you have an older copy of SImplyMEPIS that does not include the /floppies directory, you can download the files in this zip: floppies.zip Then unzip the zip and follow the instructions in README.txt