Factory Restore before installing Win10

Hi ,

I cannot find the instructions on how to restore  the factory default settings for Dell Alienware X51 R2.  I want to have a clean system before I allow the upgrade to Win10.

http://www.dell.com/support/Article/ie/en/iedhs1/SLN147555/EN   suggest that these instructions applies  only to Dell Precision, Latitude, Optiplex and Vostro computers.

I thought that Dell had a hidden partition and you could access the rebuild process from there.

I would really appreciate the help, please.

Tommy.