Create Virtualbox image of a physical partition

There's a documented "internal" function that you might be interested in. You can create a "raw disk" image which basically passes all commands to the partition on your hard drive. That way, you can keep your Windows partition and attempt to boot it from VirtualBox as well.

You can create a raw image as follows:

VBoxManage internalcommands createrawvmdk -filename /path/to/file.vmdk -rawdisk /dev/sda -partitions 1,5

where 1,5 means partitions 1 and 5 on /dev/sda

Mind you, the chances of this working flawlessly are pretty slim. Windows is not exactly known for being adaptive to extreme changes in hardware.

You can read more about raw disks here: 10.8.1. Using a Raw Host Hard Disk From a Guest

As Matt said, you use the VBoxManage command, and that Windows might not like it. However, there's a faster way that doesn't use up as much disk space. You can use stdin as the input for the convertraw command (which, if you read Matt's answer, is the same as the convertdd command:

# dd if=$WinDevice | VBoxManage convertfromraw stdin windows.vdi $Bytes

Where $WinDevice is the device of the windows partition (such as /dev/sda2), and $Bytes is the exact number of bytes (for example, 1488581554176; you can determine this from within Windows by right-clicking on the C: drive in My Computer and hitting "Properties", it's the Capacity: line underneath the Used and Free space lines and above the pie chart).

Note that I have not tried this myself, and that I believe you might need to use /dev/sda instead of /dev/sda2, assuming you won't be writing to the drive that Windows is on. That way, you capture the partition table and bootloader.

I was just trying to do nearly the exact same thing, albeit from Ubuntu. I didn't want to create an image of the entire hard drive, and it didn't seem like a good idea to me to use the physical disk with the VM. I finally found the solution:

1. (Recommended) If you don't have a Windows disc or ISO, download an ISO. I used X17-59465.iso

2. If desired, shrink the windows partition so the image size will be smaller. I prefer to do this from Linux using GParted (to avoid "umovable" files that are in use), then reboot to Windows, let it do a chkdsk, and reboot back into Linux.

3. If mounted, unmount the windows partition just to make sure it doesn't change while imaging it

   sudo umount /windows
   

4. Install the MBR package. On Ubuntu:

   sudo apt-get -y install mbr 
   

5. Create an image of the MBR (change the device as necessary)

   sudo dd if=/dev/sda of=mbr.img bs=512 count=1
   

6. Install a fresh MBR on the image, to get rid of GRUB

   sudo install-mbr mbr.img
   

7. Create a raw VMDK image that will mirror the existing partition layout (change the device and partition as necessary)

   sudo vboxmanage internalcommands createrawvmdk -filename windows.vmdk -rawdisk /dev/sda -partitions 2 -mbr mbr.img
   

8. Create a VDI image that will copy the data from the partitions selected in the previous step

   sudo vboxmanage clonehd windows.vmdk windows.vdi --format VDI
   

9. Change the ownership of the new image file

   sudo chown $USER. windows.vdi
   

10. Cleanup

    sudo rm mbr.img windows.vmdk windows-pt.vmdk
    

11. (Optional) Compact the new disk image

    vboxmanage modifyhd windows.vdi --compact
    

12. Create a new Windows 7 VM, using the image you just created for the hard drive

13. You can try to boot the VM, but it might fail. If it does, boot the VM to the Windows disc/ISO → Repair your computer, and if given the option click Repair and restart

Sources:

• https://unix.stackexchange.com/a/64496/14436
• http://philatwarrimoo.blogspot.com.au/2014/01/virtualize-old-windows-xp-disk.html