Try clearing CMOS

Also, what was wrong with it (that caused you to reset it)? 

I am selling it and had to reset it to factory settings. Now it's not working. Also, this is not an accepted solution, I just accidentally pressed that.

Also, after about a minute of being on and showing a black screen. It shuts itself off again and turns itself on again, continuing this process. 

I turned on the pc after doing that and all I get is a black screen. Nothing is showing up? What should I do now. 

I removed the accidental solution. Did you try the CMOS reset as per above instructions?

Yes, I followed the instructions there. Now when I power up the pc, it stays on, but the screen just stays black. Windows doesn't boot up and nothing comes up on the screen.

Do a search for F12 it will bring you to the ePSA Diagnostics for the R7. Maybe it will shed some light on the issue. Also see the Flea Power Release.

https://www.dell.com/support/home/en-us/product-support/product/alienware-aurora-r7-desktop/docs

https://dl.dell.com/topicspdf/alienware-aurora-r7-desktop_service-manual_en-us.pdf