Step 1: Preparing the USB key
Since the WIM file we are creating (see Step 2) will be larger than 4 GB, the USB stick needs to be formatted with NTFS. In a command prompt with administrative rights, do the following ("clean" will permanently erase the contents of your USB key!!):
select disk 1
create partition primary
select partition 1
format fs=ntfs quick
The above assumes that the "list disk" command showed you two disks, "Disk 0" being your internal hard disk and "Disk 1" being the USB stick. Your system might be different. "clean" will permanently erase the contents of your USB key!! Ony my system, the "assign" command put my USB key on drive H:, this could also be different on yours.
Next, copy the contents for example of a Vista Windows 7 CD to your USB key:
xcopy f:\*.* /s /e /f h:\
Your USB key is now ready to go.
Step 2: Creating the "Monster WIM"
The WIM format introduced with Windows Vista is basically a container for one or more OS images. You can have a look into such a container by starting the WAIK command prompt (see your Windows start menu after installing WAIK) and entering the command "imagex.exe /info x:\sources\install.wim" (assuming x: is your DVD drive). The output will look something like this (some output snipped):
C:\Windows\system32>imagex.exe /info f:\sources\install.wim
ImageX Tool for Windows
Copyright (C) Microsoft Corp. All rights reserved.
Image Count: 6
Part Number: 1/1
Relative path junction
Available Image Choices:
As you can see in the partial output above, the WIM contains 6 images; I've included the more important parts of the first two images. Creating the actual WIM is now straightforward enough:
imagex.exe /compress maximum /export f:\sources\install.wim 1 d:\temp\install.wim "Windows Server 2008 R2 Standard (FULL)"
imagex.exe /compress maximum /export f:\sources\install.wim 2 d:\temp\install.wim "Windows Server 2008 R2 Standard (CORE)"
Now insert the next DVD, say with Windows Server 2008 x64, and repeat the process (run "imagex.exe /info …" to see which images to get):
imagex.exe /compress maximum /export f:\sources\install.wim 1 d:\temp\install.wim "Windows Server 2008 Enterprise x64 (FULL)"
imagex.exe /compress maximum /export f:\sources\install.wim 2 d:\temp\install.wim "Windows Server 2008 Enterprise x64 (CORE)"
You don't have to worry about numbering in your newly created WIM file; imagex.exe will assign them automatically in ascending order. If you want to get rid of an image in your WIM, use:
imagex.exe /delete d:\temp\install.wim 1
Step 3: Copying the new WIM file to the USB key
All that remains to do is replacing the "install.wim" on your USB key with your customized one:
copy d:\temp\install.wim h:\sources
Select "Yes" if prompted to overwrite the existing install.wim.
Also take a look at this link http://g0b3ars.wordpress.com/2009/09/20/create-an-all-in-one-win7vistawindows-server-2008-discusb-stick/