Guide to installing any Windows OS through USB with the help of a pen-drive Things you will require :- Windows 7 USB Tool ( also works with windows8 iso's) - images2.store.microsoft.com/prod/clustera/framework/w7udt/1.0/en-us/Windows7-USB-DVD-tool.exe An iso file of the windows version you wish to install on your system. ( follow steps to create an iso image from a digital media dvd/cd etc ) A pen drive of suitable size to contain the iso. Steps to make an iso image if you have a digital media :- Download free iso creator. ( You can also use other software to create an iso but this one is free ) Download Free ISO Creator Install Free ISO creator and run. Select your cd/dvd drive with the windows disc in it as the source folder. Name it whatever you like in the volume section. Click on Save as button and browse the path where you will like to save the iso on your system, name it as Windows ( can be anything ) Press create and it will start creating an ISO from the source. Wait till the process is done and you are ready with an ISO of your favorite OS to put it on a pen-drive and install. Steps to make the pen-drive boot-able with the OS :- Install Windows 7 USB Tool. Open the Windows 7 USB/DVD Tool from start menu or desktop. Browse and select the iso image to your OS and press next. Select media type as USB device. Select your USB device in the drop-down list and click BEGIN COPYING. When the copying has finished , you will be ready with a boot-able pen-drive with the OS of your choice ready to install. Restart the PC and chose USB as boot device and follow the instructions on screen to setup the OS from the pen-drive. Note : If you are trying to create a boot-able pen-drive with a x64bit iso image and running the usb tool to do so on a x86 ( 32bit ) system .. you might end up getting an error. Following are the steps to achieve the same without facing any kind of errors. Login to your Microsoft Store account to view your purchase history Look for your Windows 7 purchase. Next to Windows 7, there is an "Additional download options" drop-down menu. In the drop-down menu, select "32-bit ISO." Right-click the link, and then save the bootsect.exe file to the location where you installed the Windows 7 USB/DVD Download Tool (e.g. C:\Users\username\AppData\Local\Apps\Windows 7 USB DVD Download Tool). Once the file has been saved, go back to the Windows 7 USB/DVD Download tool to create your bootable USB device. When all is setup you will need to boot from the usb device to start installing the OS. For this you will need to change boot options in the BIOS of your system. Reboot the system. While booting (before Windows starts loading), get into the BIOS configuration screen by hitting something like F1, F2, Delete or Escape. Hotkey instructions are generally provided on the screen. Go to the section that contains your boot devices. With your USB drive plugged in, the USB drive should be listed. Select it . Exit from the BIOS configuration, saving all changes.