How would you like to run an entire operating system as a program in windows?
Yes it can be done all right by making use of a software called Virtual PC. It is a software released by Microsoft to run a virtual machine that is an operating system as a program in windows. You can download it from the Microsoft website. Just Google for it.
However it is recommended that you have at least a RAM of around 1GB for the efficient use.
You just need to have the live or bootable CD of the operating system you want to run as a program.
You can also use .ISO image files of the operating systems you want to run.
Just run virtual Pc and locate the iso image of the OS you want to boot and it will boot as a program in a new window in windows Xp or vista.