Melodie, I cannot access that page ....... probably in French anyway so I would be lost 
I quoted the poor man's install (in english... )from the ancient wiki that has disappeared : I got the article at archive.org.
Maybe you can display more easily than my blog (it works, but the server is a bit slow theses days).
http://web.archive.org/web/20080323043809/http://oldwiki.mypclinuxos.com/PoorManInstallOn an existing setup there is little to do ......
make a suitable entry in the menu.lst file
copy the OS files from an ISO to the location
It is the same procedure as doing it on a flash stick, except much simpler, because the drive is static in the PC, so the various things needed to allow booting on other PCs are not necessary.
I have described in the 2 preceeding posts I did, how I prepared the boot. The boot starts fine, if I boot with bootsplash I have bootsplash, if I put it "noquiet" I have framebuffer, and messages going until it looks for the image to mount, on all drives, and does not find it. If you look at the menu.lst blocktext I copied up there, you can see I put isolinux directory just under / in /dev/sda1, which is my root system, and the file livecd.sqfs just there too, under / as well.
I had mounted the iso on loop on a directory to copy theses (sudo mount -o loop file.iso /media/cd and cp -R), as I usually do for pendrive boots too.
There was an article in one of the old magazines ....... one of the first 6 I think that detailed the procedure back then. It has not changed substantially ..... maybe boot codes have changed a bit.
I have tried to see in the initscripts if I could find any boot codes, I tried all sorts of keywords with grep, in a Initscripts directory where I had extracted the content of the initscripts package, but I didn't find anything.
Maybe this would be best in a thread of its own?
I am ok with that, but actually I don't know what more could be added... unless much more can be said ?
