can anyone tell me where can i get custom-made operating systems.. what i meant by custom-made operating system is self created systems or combination of systems like Mac and Windows.. I did saw people using such systems so can anyone tell me more about it??
Any distro can dual boot multiple operating systems. You just need to modify GRUB's menu.lst, it is pretty trivial. Just install Linux last. Windows is so self righteous that it just stomps all over anything preexisting on your hard drive. Self made operating systems? Arch and Gentoo come immediately to mind, you are in control of the entire installation start to finish. Debian I believe can also be installed in a similar way, but isn't the default way. If you are hardcore, look up LFS (Linux From Scratch), it doesn't get more custom made than that.