Wow, that's really strange. I've never come across a system that can't have the BIOS modified to change the boot sequence or method.
Still, "they" say that you learn something new everyday.
So, if you follow the following links, that's what Mandrake have to say on the matter
Quote taken from the Mandrake linux website.
All recent systems can boot from a CD-ROM. Look for Boot sequence in the BIOS' features setup, and set the CD-ROM as the first boot device. If your system cannot boot from a CD-ROM you will have to use a floppy
and this is the link
to follow to get mandrakes instructions on how to do that.
It also makes mention of installing via a network, but as I've not done that, or used a floppy to install I can't give you a "punch by punch" routine.
But, additionally to the mandrake forum here at LQ (a sub forum in the distributions forum), you should also be able to find idea's and suggestions here
I've always found the advice good, though you often don't get answers quite as quickly.
The last thing that I was prompted by at mandrakes site, is the "old cherry" of modem's. If you are using dial up, then you may still have problems. You would need to check to see if your modem is what is know as a "winmodem". If you hit the "next" page when looking at the mandrake page that I've linked above, you get the page about "supported hardware" and there's a link about winmodems at the bottom of that page.
Sorry I can't be any more specific.