How to format and create a bootable USB flash drive (e.g. stick/pen/USB drive, memory stick)

Some years ago in a post related to useful free tools and among them I listed the Windows USB/DVD Download Tool. It allows to extract an ISO on a USB pen (greater than 4GB), avoiding to waste a DVD when you have to instal a new program or a O.S. . Moreover now PCs have no built-in DVD player so the USB pen option become really a must! That tool is quite old and refers to Windows 7 and so it requires the Microsoft .NET Framework 2.0 that is not available in WIndows 10 by default, so you could have to install it from here (choosing the version you need, possibly NetFx20SP2_x64.exe if your PC is an Intel one) as stated in this instruction.

Luckily there are now other possibilities, even though that tool can still be used after having installed the required old framework. In particular I used Rufus, a reliable USB formatting utility that is available for free from a GIT project. You can find a useful translation in italian of the instructions in this site.

Its use is anyway very simple. After choosing the USB key device, if you want to install an ISO image, you have just to select that option in the boot selection. The only possible trap is that one combo-box (step 1) is also a button so, after selecting the SELECT option, you have to click on it to have the popup windows open so you can select the proper ISO file (step 2).

After clicking START button, you are warned that all data on that USB device will be destroyed:

It may happen, if the PC where you want to install the program is quite old, that a message like the following will appear when you try to install the program (e.g. Windows 10):