How to install windows 10 from a usb

First Off, the Requirements

In order to create a bootable Windows 10 Technical Preview USB drive you will need to prepare the following, before we can go any further:

• Windows 10 Technical Preview ISO, which you can download from here;
• Windows 10 Technical Preview product key: NKJFK-GPHP7-G8C3J-P6JXR-HQRJR (taken from the page linked above);
• USB drive -- the minimum size is 4 GB for the 32-bit version and 8 GB for the 64-bit version. Also, the faster the USB drive is the less time everything takes;
• Windows PC.

Creating the Bootable USB Drive:

Step 1:While that ISO file is downloading, grab the aforementioned Rufus utility. It's portable, meaning it doesn't require installation.

Step 2: Run Rufus, then insert your flash drive, making sure it doesn't contain any important data. (It's about to get wiped.) Rufus should automatically detect the drive and list it in the Device field. (If not, select the drive manually.)

Step 3: Notice the check box marked, "Create a bootable disk using." Click the drive icon at the far right, then navigate to wherever you saved the Windows 10 ISO file. Select it, and then click Start. (All the other default settings in Rufus should be fine.)

Step 4: This will take some time, perhaps as long as 20-30 minutes. Don't be alarmed (or confused) if an Explorer window appears for the flash drive; just leave it alone until Rufus reports "DONE." Then you can close the program and drive window and remove the drive.

Step 5: Now it's time for the old PC. Plug the flash drive into a USB port, then power up the system. Most likely, it won't be configured to boot from an external drive by default, so you may need to jump into a startup menu or the BIOS during the POST. Ultimately, you need to force the machine to boot from the flash drive. Once you've done that, reboot, then follow the Windows installation instructions.

And that's about it! Take Windows 10 for a test-drive, then hit the comments to share your thoughts on the new OS.