dual booting windows 7 or windows 8 or both

In order to dual boot there are a few things you need to know in order to have fewer headaches
when setting up dual booting...

a: windows 7 ultimate can not exist on the same hdd as windows 7 pro or windows 7 home
or windows 8 pro etc and visversa...absolutly none of these os's can exist on the same
hdd with any of these other os's on the same HDD.. ...

b: you can install 2 or more windows 7 ultimates on the same drive or 2 or more w7 pro's
or 2 or more w7 homes premiums , but you can not mix them on the same hdd. therefore they must all have
thier own HDD to be installed on.

c: that means that ALL HDD's must be unplugged accept the HDD you are installing the new os on.

d: why... because all these os's have (create) system partitions that are all incompatable with each other
and all os installs automatically seek for a compatable system partition and if it finds an incompatable
system partition the install will Terminate. if the install does not find any system partition
you will need to delete any partion and create a new partion and it will create a new system
partition...and in order to successfully boot it must have a new compatable system partition.
follow the prompts to install the os on the larger partition...do this for each os install

E: when the new os is installed go into the bios to document which hdd is set to have the top
boot priority in the boot sequence and boot the puter to document a succesfull boot... and let
the install finish...then plugg all the other hdd's in and if it does not boot goto the bios
and reset the boot priority.

F: allways set the boot priority in the bios to the hdd with the higher os ...
( w8 is higher than w7 and w7U x64 is higher than w7U x86 and w7U is higher than w7Pro...etc )

G: boot to the higher os (this is a must ). then add the other os's to the bcd registry with
easybcd editor.

H: after successfully setting up your duel boot system backup your bcd registry on multiple hdd's

if you loose your higher os for any reason... do all this over again accept resetting up your duelboot
in the bcd registry.. just import the backup and you should be good to go unless you rewired all your
hdd's to differant ports or physically moved them.if you put everything back the way it was and you have
some problems you may have to adjust drive letters in the bcd registry with easybcd editor...

I: Finally if you follow these guidlines dual booting will be easier and a lot more fun

p.s. Properly lable each hdd's cable ( sata 0,sata 1,sata 2 etc) and drive ( windows 8 windows 7 ult
windows 7 pro...etc) physically and with the hdd name in the system and you will have less headaches
setting up multiple dual boot i.e. 3 or more os's on the same puter..

FYI Gene Vantreese



Mostly Harmless
Staff member
Hi Gene,

Actually, our recommendation is to always keep the hard drives connected. That way, you'll never need to modify BIOS settings. If it's a newer OS you're installing, it'll upgrade the old bootloader. If it's an older one, use EasyBCD to install latest bootloader.


Knows where his towel is.
Staff member
And if you want separate, independent installs of any Windows OS, you can disconnect other drives physically, but you don't necessarily need to.
Just make sure that when you run setup, for whatever version of Windows you install, that only one partition on the PC is "active", and that partition is the empty one you want to install into. That way the new OS will be "C" (regardless of any other Windows partitions that might exist), and will contain its own boot files which will boot the new OS, and no other.
Do the same for every install and they'll all be fine and unaware of any other OS.
Each will only be bootable by setting it "active" when you want to boot it.
Once all OSs are installed and verified, set the newest one active (i.e. W8 if you have it, or W7, Vista, XP in that order), and use that OSs boot files to boot all of the others by adding entries for them into the BCD (or boot.ini, if you only have XP systems).