Did you buy this motherboard or was it pre-installed?
Secondly, look on the motherboard for a possible sticker or labeling with S/N on it. It's possibly on there and that could be used to identify which motherboard model you have as well.
Do you know the model name of the prebuilt?
then you can go to the dell website and
look up the manual for it they will have it
you can use CPU-Z to get the model number
I need suggestions on a good motherboard, price range $200-$400, I found one any opinions? GIGABYTE G1 Gaming GA-Z170X-Gaming 7 (rev. 1.0) LGA 1151 Intel Z170 HDMI SATA 6Gb/s USB 3.1 USB 3.0 ATX Intel Motherboard