Although there are many methods to install Windows 7 from a USB drive, most of them are quite complicated and well, quite difficult if you are a complete noob. Fortunately the method I am going to discuss in this post is a lot easier and only comprises of a few steps. So here it goes:
The first thing you need to do is to download and install a software called UNetbootin. You also need a Windows 7 ISO image file in order to install it onto your computer.
Now insert your USB drive and run the software. Select Disk image as ISO and browse for the Windows 7 ISO image file. In the type column, select USB and choose the drive. Click OK and the extraction process will begin (it wil install files onto your USB drive).
Completion of the above process will result in the USB drive becoming a bootable Windows 7 installation, meaning you can now install Windows 7 on your computer/netbook/laptop using your pen drive.
If you want to install Windows 7 on your PC right now, restart it and when the system is starting up, bring up the BIOS Boot Menu using any of the following keys : F1/F2/Escape etc. Select ‘Boot USB by default’ and press F6 to apply the changes. Now restart your system and the first thing that will come up when starting up is the Windows 7 Installation. Now simply install Windows 7 using the directions on your system.