When you finally make the decision to start fresh with a new OS on a new hard drive, it can be nerve-wracking. If you’ve been following proper hard disk etiquette, most of your programs and data should be stored on different drives or partitions than your operating system, but somehow important data has a way of making its way onto your C: drive. And although you can do your best to make sure you back up all the data you want to keep (your My Documents folder, for instance), it’s hard not to feel like you’re forgetting something.
You don’t have to worry. Thanks to new tools from Microsoft in Windows 7, you can preserve your entire hard disk on another drive as a Virtual Hard Disk (VHD). So don’t worry that you’ll forget important data on your old drive—just freeze it solid, like Han Solo in a block of carbonite, and rest easy knowing that if you suddenly recall that you left something important on your drive, you can simply run it as a virtual PC, or mount it to your new system.
There are several programs that will allow us to accomplish our goal, but only a few that are both free and simple to use. For this how-to, we’ll use Windows Virtual PC and Disk2vhd. Both programs are free, but there is a major limitation: Windows Virtual PC only works with disk images of no more than 127GB in size. Fortunately, this is enough for many Windows XP–era boot disks, but not all. If your drive is bigger than 127GB, you can still create the VHD using Disk2vhd, and you will be able to mount the VHD as an additional hard drive, but you won’t be able to “boot it up” using Virtual PC.
1. Create a VHD
The first thing you must do is create a virtual copy of your C: disk while it’s still your boot drive. This is made very simple with the aforementioned Disk2vhd, which exists for just that purpose. Even better, Disk2vhd works while the disk is online, meaning you can install and run it while still using the drive you intend to clone. Simply download the program here and unzip. When you run the executable, you’ll be asked to specify one or more drives to clone, and an output destination for the .vhd file (image A). Make sure you’ve got another disk with enough space to save the virtual disk, which will be the same size as the original.
That’s all the direction Disk2vhd needs. After that, it’ll take its time making a perfect copy of every disk that you selected in the first step.
2. Recover Data from the Disk
So, now you’ve created your virtual hard disk, installed your new OS, and a month or so has passed. Suddenly, you remember a very important file that you forgot to get off of your old disk. How do you retrieve it from the VHD file? There are two options:
1) Recreate your old machine using Virtual PC
This is the most straightforward case, but it only works as long as your VHD is 127GB or smaller. If it is, you can load it into a virtual machine created by Virtual PC. To use Virtual PC, you’ll first have to download it from Microsoft. At the bottom of the page there are three download options, with the instructions to download them all (image B). You can actually skip the first and third downloads, which simply create a premade virtual machine that will allow you to use XP Mode in Windows 7. (If you don’t have Windows 7 Professional or higher, you’ll have to use Virtual PC 2007.)
To create your virtual machine, simply press the Start button and type vpcwizard into the Run bar. This will walk you through the simple steps involved in creating a new virtual machine for your saved hard drive. The most important step is the one labeled “Add a virtual hard disk” (image C). Here, click the second radial button, labeled “Use an existing virtual hard disk” and browse for the disk you created earlier. When you’re done with the wizard, you’ll have a virtual version of your old machine, which you can use to locate any old files or applications you may have forgotten.
2) Mount the virtual drive
If your VHD is too large for Virtual PC, you can still mount it to your new computer as a regular hard drive. To do this, first open the Computer Management window by clicking the Start button, then right-clicking Computer and selecting Manage. In the Computer Management window, click Disk Management, then click Action and select Attach VHD (image D).
You won’t be able to boot from the virtual disk, but you should see it in the Windows explorer as though it were a real hard drive. You can now browse through its contents and find any files you need.