I prefer using the mentioned tool to burn the installation files to a bootable USB stick.
why?
open it by copying all the files from the windows dvd to external USB HDD easier?
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I ask it because I did not find a tutorial installing windows from USB external drive (HDD) in this forum
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Tutorials for Installation media types for Windows 7
USB Windows 7 Installation Key Drive - Create - This will show you how to create a USB flash key drive that you can boot from to install Windows 7.
Windows 7 USB/DVD Download Tool - If you would like to burn your downloaded or converted .iso image to a DVD or create a bootable USB flash drive, this free Microsoft utility is for you.
Install Windows 7 Without Using Any External Device - With this you will be able to Install Windows 7 as soon as you download the ISO and extract it.
Burn Disc Image - ISO or IMG file - This will show you how to use the built-in Windows Disc Image Burning Tool to burn a CD or DVD disc image from a ISO or IMG file in Windows 7.
For Advanced Users
Install Windows 7 FAST without a DVD or USB device - This method uses technology designed for advanced users. It doesn't require extra bootable media and it leaves your existing Windows install intact. It's fast, it's flexible and it's all command line suitable for scripting.
Make bootable iso from student d/l - How to make an ISO file with the student down load that has these 3 files : Windows 7-HP-Retail-en-us-x64.exe, setup1.box and setup2.box.
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http://www.sevenforums.com/installa...ck-reference-list-installing-windows-7-a.html