Configure Two Operating System in One Machine

Clarifications

hard drives. The way you install and setup will depend on the two operating systems.

Software developers do it all the time so that they can test software on different operating systems.
If you are going to do it I would advise you to install each operating system on a different hard drive, this is not strictly necessary but it seems to cause less problems in the long run.
You will need an installation disk for each of the operating systems you want to install AND a valid license for each of them.
If you need more info on how to proceed post back here when you are ready to have a go

First create the partitions of ur harddisk and install the higher version of OS in the primary partition and then go to another partition to install lower version of OS
eg: xp-sp3 is higher than xp-sp2!