I have Vista installed on my computer and i want to install windows xp (boot from xp cd) without formatting. Is this possible? i remember something a long time ago when there was an option to only delete the existing installation instead of formatting the hard drive, but am i remembering this wrong?
You could have a dual boot system with both Vista and XP click here
I assume you have an unregistered copy of XP or a full retail copy plus the Vista Disk which you will need for this. Do read the article through carefully. Someone else may be able to provide a better or alternative tutorial.
If you may want to Restore Vista at a Later Date I suggest you first buy and use Acronis True Image, and create a Image of the Vista Partition before removing it, this you need to save to another Drive