How to prepare a USB thumbdrive to boot and install Windows 7 Prerequisites: Your BIOS supports booting to USB device, and that functionality has been enabled. Your empty USB device had 4GB free space (or more) available, and you’ve removed all other important files from this stick. This process will WIPE IT CLEAN. You have been warned. You’re using Windows Vista (or newer) DISKPART. NOTE: Don’t insert the USB memory stick just yet. I’ll tell you when. Open a command prompt as administrator. From the C:> prompt, type: diskpart From the DISKPART> prompt, type: list disk Make mental note of the disks you have. Then, insert your USB stick, and list disk again. You should see a new disk with a new number. That’s the number you’ll use in the next command: select disk X (where X is the number for your USB drive). To make sure that there’s nothing on the USB stick that will interfere with our booting, we’ll wipe out any partition information on the stick. WARNING! This will wipe this stick clean! It will delete and destroy any data on this stick. From the DISKPART> prompt, type: clean Now we want to create our primary partition for booting. From the DISKPART> prompt type: create partition primary Now we want to change to that partition and make it an active or bootable partition. From the DISKPART> prompt type: select partition 1 When that step completes, type: active Next we need to format our active partition and assign a drive letter to the boot partition. From the DISKPART> promp,t type: format fs=fat32 quick When the format completes, type: assign You can now exit DISKPART and close the command prompt. The USB stick is now ready to boot. Next, just copy the files from the ISO (if you’ve mounted it using a tool which does this) or from the Windows 7 DVD onto the stick.