Dual Boot Windows 7 on Vista via VHD file

I love and depend on virtual machines to test software and system configurations. In most cases, it is sufficient for my testing purposes. One drawback of this is that it isn?t a ?true? test of the operating system?s performance since the hardware used is being virtualized via software.

There are lots of guides around the net as well as utilities that can assist you in configuring a system to ?multi-boot? different OS versions off the hardware, but these can be a bit challenging to set up for average folks. Recently, while I?ve been playing with Windows 7 Beta in Virtual PC 2007 sessions, I?ve been itching a bit more to try the performance on real hardware, but I haven?t wanted to commit to wiping one of my systems entirely clean first.

Nor did I want to fuss with a pure Vista/W7 ?dual-boot? configuration as they traditionally are done. Instead, I knew that Windows 7 brings with it an exciting new feature, that is perfect for this particular case; it supports booting a system from a VHD file.

However, I?ve got a slight issue. Windows 7 uses updated bootloader files to make that happen. Windows Vista uses similar files, but those versions don?t support VHD booting. I don?t want to install Windows 7 to be able to boot a VHD of Windows 7; that kind of defeats the intended purpose for me. Most all the guides on doing this only describe how to pull it off that way.

No, what I want to do is to keep my local Vista install intact, and somehow boot into a VHD of Windows 7?thus running it ?live? on the real system hardware instead of on virtualized hardware. Can it be done? Yep. I?ve had to pick at a number of posts to spin this thing together.

Credits for source material in all their fantastic goodness at the post end but up front, prime props and hat tips go to Aviraj Ajgekar and Adrian Kingsley-Hughes. I?ve copied some of their steps because they were so good, I had little to add. You will need a couple of things first: Ensure you have a copy of a Windows 7 beta setup DVD handy. You can use the ISO file itself to get started however you will need the burned DVD at some point.

I also found it helpful to use my WinPE 3.0 custom boot disk. This is optional, but could be handy. And you will need a Vista-installed system. Warning: proceed at your own risk. You might tank your Vista system if not performed correctly. I recommend practicing on a Virtual PC VHD with a Vista install first a few times. What has worked fine for my on my system might be an issue for you.

The screen shots included in this post were obtained from a walkthrough of these steps as performed in a Virtual PC session with the free Microsoft Vista IE App Compat VHD as the primary OS.

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Posted By: raj11650
10 May 2009