Preface: Alienware-15-r3 the system installed by default is WIN10. Now uninstall Win0, install Ubuntu 16.04.3 LTS.
One, download ubuntu 16.04.3 lts image file,: Https://www.ubuntu.com/download/desktop
Second, make USB boot disk with Uitraiso
1, uitraiso:https://cn.ultraiso.net/xiazai.html
2, Uitraiso registration code (PRO-Test available): http://www.zdfans.com/3740.html
3, install Uitraiso, click Free to use, or after registering, make USB boot disk. For detailed steps, refer to: https://jingyan.baidu.com/article/a378c960630e61b329283045.html
Third, install Ubuntu 16.04.3 LTS
1. Because the ALIENWARE-15-R3 motherboard has the UEFI Secure boot feature, this will cause the Ubuntu 16.04.3 Lts to not start after installation. You need to enter the BIOS settings, change the state of secure Boot from on to off, and then save.
2, install Ubuntu 16.04.3 LTS, after installation, restart, you can start normally.
Alienware-15-r3 installed Ubuntu 16.04.3 LTS