
Note that there are some pitfalls with this Windows USB drive once you have successfully made it: some netbook Atom 32-bit CPUs) won't run a 64-bit OS, so a 32-bit version of Windows 7 is usually best for these. use a Windows 7 64-bit PC to install say Vista 32-bit OS from a Vista 32-bit installation DVD onto a USB drive, or use a Windows XP system to install Windows 7 64-bit onto a USB drive using this method. The instructions below assume that you have a USB drive (USB Hard Disk - recommended, or USB Flash drive - slow!) and you want to install Windows 7 onto it using a Windows 7 install DVD (or ISO file) as the source. It also now automatically finds and uses the 3 files that are needed from the MS WAIK, so you don't need to manually copy them first. The instructions in that forum post #1 & #2 and some of the prompts in the installer.cmd file that fujianabc provides were however confusing and potentially dangerous (you could accidentally corrupt your system drive) - so I have slightly modified his script to make it clearer and easier to use.


This tutorial as based on fujianabc's Reboot.pro forum post 'NT 6.x fast installer: install Win7 directly to USB external drive' and his excellent scripts (now with reg tweak by 'cdob' from reboot.pro -USBBootWatcher is no longer required). it does not matter what is on the internal hard disk of the target system, even if the internal hard disk is broken/not working.
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This tutorial does not make a Windows installer USB drive, it actually puts a copy of Windows 7 onto a USB drive and makes it bootable. For 'Removable' USB flash drives, be sure to choose the VHD option (for Win8/10) or it won't boot!

NEW! You might like to try WinToUSB which make it very easy to prepare a bootable USB drive containing Win7/8/10 To Go. So now you can try Windows 7 without needing to install it onto your internal hard disk! IT WILL ONLY WORK ON A USB 2.0 PORT (see instructions at the end of this page for instructions on how to add USB 3 drivers). Please note: This tutorial enables you to prepare a USB drive so that you can boot directly to Windows 7 from the USB drive.
