You will need Windows 7 Waik and Windows 8 DVD of ISO

First we want to extract our .wim file from our Windows 8 DVD or ISO.

We do this by opening the DVD and navigating to the sources folder, the Install.wim is located there. Drag and drop to C:\.
If you have an ISO open with WinRAR or UltraISO.
Now we have to make a .vhd
1. Right click on Computer and click Manage. The Computer Management console will open
2. In the left hand pane click Disk Management
3. Right Click on Disk Management and in the pop out click create VHD.
4. Navigate to a folder and give your .vhd a name. I chose C:\W8CPx64(if you do the same as me it will be easier to understand this walkthrough) I made it 60GBs in size.

You will have to wait a few minutes until your .vhd is created.

Now we are going to put this disk online.

1. Right click on the disks name in the Disk Management pane and click Initialize Disk (.vhds are always coloured blue)
2. Leave the selection on MBR (Master Boot Record) and click OK
3. Right Click on the Black Unallocated area and click New Simple Volume, then click next and ok until the Wizard has set up your .vhd for you.

The next step is to place the Windows Image we extracted earlier onto our .vhd and boot from it.

1. Click Start\All Programs\Microsoft Windows AIK\ Deployment Tools Command Prompt
2. To install windows on your .vhd run this command imagex /apply C:\install.wim 1 H:\ C:\ the location of the install.wim and H:\ the location of my .vhd.
3. That should take a few minutes. Once it has finished close Deployment Tools Command Prompt.

Now we need to set up our PC so we can boot off the .vhd. We need to use our command next. Type
bcdboot.exe H:\Windows and then exit

Reboot and you will see the Windows 8 dual boot screen and be most of the way through installation.