How do you burn Ubuntu to a cd 700MB for a laptop that has no operating system?
i guess you only used ubuntu with the windows installer or something similar before.
A ubuntu (or any other distro) can boot up a system on it's own. no need for an OS there at all. In fact, even if there was an OS installed, it would be irrelevant to starting the ubuntu install.
Just burn the CD, and configure your BIOS to boot from it. if it's a newer computer, UEFI may give you trouble, but read on and you will be fine.
It is possible (if you do not have another PC to burn the CD, don't want to learn how to, or just don't want to) to buy Ubuntu 12.10 32-bit Desktop. It costs £4.71 and can be found here.
You can't easily use a CD, which normally only hold 600MB.
You can't create a DVD or USB boot disk, with no application or OS on the machine.
You can create a boot DVD using Mac, Windows, or a friend's Linux PC (the preferred method).
Best option: Get a friend to create a boot USB drive, on the current release of Ubuntu.
Fall-back option: Use DVD burning software (on Windows/Mac) with downloaded .ISO file here.
Cheat method (may work): Purchase magazine with attached bootable USB or DVD of your preferred Ubuntu version.