In Windows Xp, you can install two operating systems on the same hard disk of one computer.
Whether you have two copies of Windows Xp, or two different operating systems, then you end up with dual boot machine when you restart your Windows Xp computer.
Dual boot means, the system will give you a choice of two operating system. For example, if you have two Windows Xp copies A ans B, the prompt will offer you to choose A or B to boot from.
Also, dual boot machine can be used to have Windows Xp, and Linux O.S. installed on the same computer.
In the case where you have two windows Xp copies on the same hard disk, you will experience a slow performance in your system.
If you need to delete one Windows Xp copies, and leave only one, here is how you do it:
When you restart your system, and you get a choice of two operating systems, you should choose the one you want to keep installed on your machine.
Once the startup process is done, and your computer is ready to accept tasks to perform certain functions, you click on the "My Computer" icon and locate the hard disks, removable storage devices, and more.
In the hard disk box you should see two drive icons, like "C", "D". If the copy you installed later need to be cancelled, it must reside on the "D" part of the hard disk.
This is because the "C" is where you initial copy of the Windows Xp resides, and it is the one you want to keep installed as the only copy on your computer.
The way you should get rid of the "D" copy is to format the "D" part of the hard disk. just right click it, and choose format. This will delete the Windows Xp copy you don't need.
In summary, you can have two operating systems installed on your windows Xp machine, which will offer a choice of loading one of two operating systems.
The good thing is that you can cancel one, and leave the other, and your computer keeps running.