RE: Unable to Install Windows on XPS 13 (9350)
After days work i found the solution. You first need to update your BIOS to version 1.1.7 at downloads.dell.com/.../XPS_9350_1.1.7.exe. Then set Secure boot "Disabled", SATA Operation Default (RAID on), Advanced Boot Options to "Enable Legacy..." and Boot Sequence to "Legacy".
After that make a bootable W7 USB stick with USB Download Tool at www.microsoft.com/.../windows-usb-dvd-download-tool.
After that you have to make your USB stick USB3.0 compatible with the Windows 7* USB 3.0 Creator Utility at downloadcenter.intel.com/.../25476.
After that you download these NVME driver at 1drv.ms/1Q39G8m to your USB stick.
Boot it and browse to the folder where you have put your drivers and enjoy.