Received a Mac Pro 2012 from eBay. Unfortunately, UPS dropped it, and there is a major dent in the bottom corner. I put a startup drive from my 2009 Mac Pro. it boots very, very slow, but it does gt to the login screen and continues (El Capitan), and I can not access Diagnostics or Recovery. The only shortcut that worked was clearing the PRAM. Sounds like a malfunction somewhere?