"In this guide I will help you find a way to install Windows Server 2012 R2 quick and easy, from a simple USB flash drive. It’s really easy, but you still need to Think about a few things. I’ll list them here and if you want, you can follow the step by step guide below.
1. Get a USB Flash drive formatted with FAT32, it has to be AT LEAST 8GB! (The Windows Server 2012R2 installation bits will not fit on a 4GB USB drive…)
2. Download and install the Windows 7 USB/DVD Download tool from Microsoft Store here or Codeplex here (It is an official Microsoft tool, totally wierdly named from the Windows 7 release but still very much valid!)
3. Download or locate a ‘Windows Server 2012 R2’ .iso file and store it locally on your harddrive.
4. Start the Windows 7 USB/DVD Download tool (from startbutton or ‘windows 8/Metro’ style startmenu’?)
5. Complete the steps 1-4
6. Insert the USB flash drive into the powered off PC to install, Power on and boot from USB drive (F9 at HP logo on HP Machines).
7. Install Windows Server as you would normally.
This guide in its entirety works just as well if you replace the Windows Server 2012 R2 .iso file with Windows 8.1, Windows 7, Windows Server 2012 or plain Windows 8 (Windows Server 2008 R2 not verified but willmost likely also work)"