You will need
  • - special build of the operating system Windows PE.
  • - PeToUSB utility.
Install the operating system on a hard disk is possible. But there are a number of nuances. For example, to install a full OS on an external hard drive is likely to fail. Rather install might work, but it will not work. Therefore, it is necessary to act slightly differently, namely to put a special build of the operating system Windows PE.
To start, you will need to download the operating system image of Windows PE. This OS version can be easily found on the Internet. After that, you will need to download the utility PeToUSB. And the last thing you need is any archiver. It is desirable to use WinRar, one of the new versions of the program.
After downloading the operating system, unzip it. To do this, simply click the right mouse button and select "Extract files". Next, select the folder in which the files will be extracted. If the context menu is not integrated functions of the archiver, to extract the image use the menu archiver.
Run the utility PeToUSB. The programs menu will list the drives connected to your computer. Select your external hard drive. Then in the program menu, locate the line Enable Disk Format, next to which checkbox.
Next, find the row Source Path To Built BartPE WinPE Files. There is a browse button. Click on this button and specify the path to the folder in which you unzipped the image file of the operating system. At the bottom of line Enable File Copy. Select the check box next to that line. After that press "Start". Begin the process of installing the operating system on your external drive. You will only have to wait for its completion. The computer to boot from external drives you can activate in the BIOS-menu.