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Step 1: Connect your bootable USB flash drive to the computer. If you don’t have one, you can follow our how to install Windows 7 or Windows 8 from USB flash drive guide to create a bootable USB.
Step 2: Boot using the flash drive and begin installing Windows. When you receive “CD/DVD device drive is missing” error dialog click on Cancel button. This action should take you to the welcome screen.
Step 3: Now, remove your bootable USB flash drive and reconnect it to a different USB port. Windows installer should now detect the drive and you should be able to continue the installation.
Source : http://www.intowindows.com/fix-a-req...dows-from-usb/