17 R3, LED light color controls

You need to use the Alienware Command Center Application. If you have deleted it or reinstalled Windows then you will have to download and reinstall it. You need the correct AWCC version for your system. The newest versions will not work on your laptop.
If you have the 17 R3 like it says above then you need this version.

https://www.dell.com/support/home/en-us/drivers/driversdetails?driverid=t5ggp&oscode=wt64a&productcode=alienware-17-r3