In this this video, Dennis Chung shows you how you can install Win7 on netbooks, which do not normally come with a DVD Drive. The video shows you how to prepare a USB drive with the installation bits and install off it.
Follow these steps for preparing the USB Disk:
1. Diskpart   
2. List Disk    
3. Select Disk 1 (Replace 1 with number reflecting your USB Drive)    
4. clean    
5. create partition primary    
6. active    
7. format fs=fat32 quick    
8. assign    
Now, a drive letter reflecting the drive should appear. Copy the bits from the DVD to the USB Stick.
[via TechNet]
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