I've had my Mac Mini for just over 5 years, and it has developed a strange problem. It reboots itself when it wakes from sleep. It will then continue to reboot itself 3-5 times with a black screen, then it will boot with the gray screen and go to the desktop as normal. It will also do the strange rebooting procedure when powering it up. For troubleshooting, I replaced my 16GB of memory with the original 4GB to see if that was the cause. The problem persisted. I then tried removing my 30" ACD, as I thought perhaps the mdp->dual link DVI adapter could be causing something. Still nothing. I then tried a full reinstall. I wiped the disk and put a fresh and clean copy of Sierra on it. The problem is still there. I then pulled the 750GB HDD and replaced it with a 320GB one I had with Lion on it. I reinstalled Lion (the OS the Mini came with), and sure enough... it rebooted again on wake from sleep. I've basically tried all new hardware that can be replaced, as well as fresh installs of the OS without any success. My question is, is there a BIOS/SMC flash for this thing? If something is corrupt, it might fix the issue. Otherwise, I'm looking at a logic board/processor replacement, and Applecare ended a couple of years ago. I'm not really in a financial position to be buying computers right now, so I'm in a bit of a crunch. Thanks in advance!