Sometimes you seem yourself in a situation where you need to install windows7 from a USB drive especially when you don't have a DVD .Here is a solution ,you can rent a Windows7 DVD from a friend and then you can create a bootable USB to install windows on your computer .Here how it works ...
First insert the DVD into your computer's dvd drive,install a program called Koala from here :
Koala USB tool
Install this program on your computer and run it.It will show an interface like the picture below
Plugin your USB drive in which you want to copy Windows7 ,click on the scan in source option (your Windows DVD)field as well as on the destination field(USB drive) .There you will see your detected source and destination if its not automatically detected.
Click on start button and wait for it to complete the process,normally
it would take 20-30 minutes to complete depends upon your computer's
performance.Once done eject the DVD or koala will do it for you as you
can check the option which says"When the whole process is complete,eject
the source disk" Browse to the usb drive under "Computer"and see if the
files have been copied to the USB drive.Click on the setup.exe to
install windows 7.
