Most netbooks don’t have an optical drive so to install Windows 7 on them, you need to create a bootable Windows 7 USB drive. Here’s how! You can also use this to install Windows 7 on your PC or Laptop if they can boot from a USB drive.
What you need for this:
Windows 7 DVD/ISO
4 GB+ USB Drive
USB Boot enabled Netbook / Laptop / PC
Follow simple steps to do this or Follow step by step through Video Below:
Step 1: Click here to download the Windows 7 USB/DVD Download tool
Step 2: Now Start this tool you will see the window (as shown below image).
Step 3: Click Browse button and select the Windows 7 ISO file from the location where you have saved it.
Step 4: Then click on Next Button.
Step 5: Select USB device button to create a copy on a USB flash drive.
Step 5: Now select your USB device and click Begin Copying button.
Step 6: Your Bootable USB Drive with the Windows 7 Installer is now ready.
You have to select boot from USB device option in the BIOS (This can be done when your PC is starting , by pressing function key Ex. F12 / F2 or DELETE key).
Now Windows 7 installation should begin. :) Video Tutorial :How to Install Windows 7 from USB