How do icreate a bootable cd

What Operating system are you using?

When making a cd bootable, you have to add a boot image to the disk where the burning app asks for it. Most apps have generic boot loaders but some installs need a special one. When making XP system files bootable, you need an image file "Microsoft Corporation.img". This image file is only 2kb in size but it tells the dos loader what to do to make the XP install cd run. If you were to download this tiny image file and changed the file extension from .img to .txt and opened it up with notepad, you would see mostly machine language and a few error codes like this:

ECDBOOT: Cannot boot from CD - Code: 0
CDBOOT: Couldn't find NTLDR
CDBOOT: Memory overflow error
SETUPLDR.BINBOOTFIX.BINI386

This tiny file when imported into a burner like Nero or even into a program like Ultraiso will create a bootable cd from a data cd set. With Ultraiso it would have a generic loader at hand but would have a place for you to point to your own for a specific boot process.

Also be aware there is a big difference between a bootable disk and an autorun disk. If you just want a disk to automatically start the setup.exe of a program from within windows (boot disks work from outside in DOS) you would add an autorun inf file with instructions inside on where to start the install. Here's a typical autorun inf:

[autorun]
open=Setup.exe
icon=Setup.exe

Added to notepad, and then changing the extension from txt to inf and adding to the root of the disk (Root means not inside any folder , it has to appear directly under the disk title name) this auto run would look for the file setup.exe in the same first part of the directory. If the actual setup.exe is in a folder the path mus be included:

[autorun]
open=Setup\Install bin\Setup.exe
icon=Setup\Install bin\Setup.exe