There are a limited number of Primary partitions available for use with Windows OSs and that number is four (4) but there can be as many Extended partition / Logical drives as there are available drive letters.
The issue is the boot files needed to boot/start Windows must be stored on a Primary partition and a Windows OS cannot / is not able to boot from a Logical partition, though with the use of the new "System Reserved" partition introduced with Windows 7 all the boot files can be stored at that single location using a single Primary partition.
This shows how to install three (3) separate OSs using a single Primary partition.
Note
As a suggestion before you start, read through this tutorial and make a plan how to proceed as to how much space you will need for each OS, I would suggest that Windows 7 / Vista be installed to at least 50GB (100GB would be more realistic) so they will have room to expand as you install programs/apps because if you run out of space it will be very hard to correct after you have set everything up.
Since I'm demonstrating this using a VM you can't go by these partition sizes.
Let's get started!
I would normally install Windows 7 first but as I want to show that Windows Vista will create boot files to the created "System Reserved" partition being the first one installed that's where I'll start.
Step One
Boot To DISKPART
If need be, view this tutorial at the link below for an out-line of the process.
How to Boot to DISKPART at PC Startup
1) Use the info out-lined in this snip to create the "System Reserved" and the Extended to get started, hitting <enter> after each command; don't be concerned with not doing anything further to the Extended, it will be done as you go along.
The
size= has to be entered as MBs : 1024MB = 1GB
You may care to have a look at
this tutorial for additional information.
The reason for suggesting to create the System Reserved at 200MB instead of the new default of 100MB is an attempt to curb some of the issues we're now seeing with the partition being too small when dual/multi booting and it also being needed for use with the Windows 7
Backup and Restore and
BitLocker programs.
click any image to enlarge
2) Now after you exit diskpart and are back at the installer, be sure to create and format a partition to do the first installation to so you don't have a hard time getting disk management to shrink the first install to a size you want,
do not use the installer to format the "System Reserved" partition you created; see these snips below.
Just do the first one to install to, the others can be done using Windows disk management after the first install is complete.
Step Two
Create the other Partitions
Now after you have the first OS installed go to Windows disk management to create the other partitions you are going to use; right click the free space; if need be view
this tutorial for the create / format process, be sure to Label (name) then during the process.
Step Three
Install the other OSs
1) Be sure to select the correct partition to install the next OS to and
do not use the installers to format the respective partitions as all the created info will be lost.
2) And here's the third OS installed.
Note: When XP is installed it isn't intelligent enough to make itself C: and not the "System Reserved" when the SysResv is marked as the "System" volume and Windows will not allow the
system volume drive letter to be removed and that may cause issues when installing programs/apps that look for C: in XP during their installation process.
Finish Up
Add an Entry for XP
If you do install Windows XP last as I have, you will have to do
at least 3 separate startup repairs with a system restart
between each repair to get Windows 7 / Vista booting again as a dual boot; see this tutorial below for the startup repair process.
How to Run a Startup Repair in Windows 7
Then an entry for XP must be added to the Windows (dual/multi boot) boot menu from within Windows 7 using the free
EasyBCD program, this is easily accomplished, see the snip below.
Enjoy! :)