Windows 7 - Dual Boot, Triple Boot, Quad Boot, Penta, Hexa, Hepta (7) Boot and beyond: This breaks the common misconception that Windows Multi-Boot configurations must be installed on “Primary” partitions. While it is true that you will need at least one primary partition, additional Windows 7 installations can make use of logical partitions thereby giving you the potential for a nearly unlimited number of bootable versions of Windows.
What are partitions and logical drives: http://windows.microsoft.com/en-us/windows-vista/What-are-partitions-and-logical-drives The above article states: "An extended partition is a way to get around a limit on the number of primary partitions a basic disk can have. An extended partition is a container that can hold one or more logical drives. Logical drives function like primary partitions except that they cannot be used to start an operating system."
But that does not mean you can not install Windows 7 to a logical partition and after completing the install boot from it as long as one or more instances of Windows XP, Vista or Windows 7 has been installed on a primary partition with or without a separate partition for the BCD store. If you plan to only install Vista and Windows 7 the process is a little different and will be covered as an addendum. For this article I’m using XP and various 32/64-Bit versions of Windows 7.
How to create multiple partitions when using a single hard drive: You will need a partition for each version of Windows you plan to install. Windows XP will be installed on the first partition which will be created during the XP installation process. You must format this partition as NTFS. For this article I am using a new unformatted 640GB hard drive.
Before we start let’s do a quick Step By Step overview of creating a multi-boot computer. 1) Install Windows XP (Do not enter a keycode or activate XP at this time). 2) Create one or two more additional ‘Primary’ partitions (Not to exceed 3 primary partitions). 3) Create one ‘Extended’ partition. 4) Create one or more logical drives large enough in size to accommodate each version of Windows and any applications you plan to install. 5) With any remaining free space create a final logical drive for sharing data between each OS. You may want to even consider creating and formatting two shared logical drives. The smaller of the two format as a 32GB FAT32 partition. Almost any OS can access a FAT32 partition. 6) Assign meaningful drive labels. This will help in identifying each partition and associated OS. 7) Place any Windows/Motherboard drivers you need on the shared partition. 8) Install Vista or Windows 7 on the second ‘Primary’ partition as is the case in this article. Do not enter a keycode or activate Windows at this time. 9) Install and use EasyBCD to rename the boot menu description. 10) Install the next version of Windows on the next available partition which is the third and final ‘Primary’ partition. 11) Once again install and use EasyBCD to rename the boot menu description. 12) Repeat steps 9, 10 and 11 until all the versions of Windows you may need (32 and 64-bit) are installed using the logical drives you created while in Windows XP. 13) What happens if I remove Windows XP?