I need to reinstall Windows 8 on my machine where I've installed ubuntu 15.04. I have no DVD drive and need to run it from a USB stick. Windows supports this but I cannot run the .exe windows file that creates the usb stick for rebooting from the USB. Hope someone have an idea on how to solve this.
You could download a trial version of windows .iso and run it in a VM (Virtual Machine like Virtual Box). Then do what you need to do in the VM, if your PC will support a VM.
Windows 7 .iso download link: HERE
Windows 10 .iso download link: HERE
Virtual Box (VM): HERE
Instruction how to install Win 7 in a VM: HERE