The install didn't go well. It went right through the extract and install process OK but then just went round in a loop wanting to keep reinstalling from the usb drive. I had changed the bios by promoting usb hdd above windows boot manager (still under uefi). So i removed the USB drive and restored the bios order. But now when i boot up i get an error window saying "the computer restarted unexpectedly or encountered an unexpected error. Windows installation cannot proceed. To install windows click OK to restart the computer and then restart the installation." It makes no difference whether i close the window or click OK, it just goes round in the same circle.
Help!