i'm fixing a gaming PC. : MSI Z370 SLI plus with 3 graphics cards. All the specs arent necessary for this post because I removed everything from the chassis and sat the mobo on the counter. Hooked it to power, monitor, keyboard & mouse. Powered it up with no drive and yet windows 10 loaded. I did this because I was trying to wipe the hard drive and after three times running disk part and reinstalling it.... Win10 would load. So I took the drive completely out....fired it up and Win10 STILL LOADS!. What in the world is going on?