what do you mean by "lan boot"?
My understanding of it says its causing a computer to boot up by sending it some sort of network traffic from another computer. I dont think this is what you want.
If you want to install a linux distro without using a live cd running from a cd-rom drive or from a usb stick then you will need to do that using a technique called "poor man's install"
here is a link that can help you do that:
http://www.pclinuxos.com/forum/index.php?topic=59127.0i have never done what the link says so i cant say anything about the difficulty level of the process