Have you ever thought that why do we need a CD or DVD Drive now a days when everyone is using a Pen Drive? Why waste CD’s or DVD’s to share data when we have Pen Drives?
One obvious reason is that these are permanent storage materials and no Virus can destroy data in a CD or in a DVD, but what if your CD or DVD-Drive is not working like mine. You can transfer data with USB but what if you need to install a windows?
You feel like what should I do now???
You need to worry little bit but not much. If you are still reading then I am going to reveal the secret about
How to Make Windows 7 Bootable USB (Pen Drive)
Prerequisites:
A Pen Drive (USB) minimum 4GB. Windows 7 is little big ( little or big.. Hehe ).
A DVD drive to copy Win7 DVD in Pen Drive. (If your DVD is not working, call your friend who has a working DVD Drive).
Little knowledge about how to change Boot Sequence to set USB as Primary Boot. (Don’t worry, I will explain this step too (After-all I am your friend, Right 
)).
Lets Start the Process:
If your DVD drive is not working, use your friends computer for this step:
Make ISO file of your Windows 7 DVD. Use Magic ISO for creating ISO image for free. If you already have any other ISO making software use that.
Time to use Windows 7 USB DVD tool -> Download OR Alternate Link.
Download it and Install.
Run Windows 7 USB DVD Download Tool from All Programs.
Now follow these steps below:
Browse already Created ISO file here.
Choose USB Device because you need to transfer ISO file in USB. Remember directly copying .iso file in Pen Drive (USB) will not work.
Choose already plugged in Pen Drive here. ( Caution: All data will be lost from the Pen Drive )
Let the Process complete. This will create Bootalbe Windows 7 USB / Pen Drive.
Now you have Bootable Windows 7 Pen Drive and you are all set to install windows via Pen Drive (USB).
Follow steps below on computer which is supposed to be formatted.
Go to your boot menu.
Start computer and press F8/F10 / Del key/F2. (Different motherboard has different key).
You need to change the Boot Sequence. Because we want USB at First Boot.
Save Boot Settings and System will Reboot. Don’t unplug Pen Drive.
Now your computer will start booting with USB Drive which contains Windows 7 setup.
Install Windows Normally.
Thats all. Easy haa!! 