Check the net for beep codes. It varies from bios to bios. Ancient stuff is difficult to deal with, that is why I flamed you with my initial response.(sorry about that). In a previous lifetime, I supported research equipment. Sometimes the vendor went out of business and the vendors that swooped in failed as well. We did HD imaging and scoured the internet for identical PCs as backups. I wish you luck on solving your problem..
I’m copying this to the others who have given good advice about my “monster” when I get back on my “main” desktop machine. (The PC I’m on now is my new Win 11 Pro machine, which I’ve been putting off getting fully set up (install 2nd HD, data transfers, apps / programs installed, etc. So, it’s pretty bare at this point, but, DOES have a spare SATA and power connection for testing (ta-da!) the HD out of my brother’s machine.)
The result:
The HD out of my brother’s machine appears to be fine, and it has Windows 7 SP1 as the OS on it. The last file modified was about 2 weeks B4 my brother passed away - right about the time he had to leave home for better care.
I’ve rechecked literally everything everyone has suggested including the PS voltages, swapped RAM, disconnected everything but the MB, speaker*, keyboard, and CPU (didn’t pull the CPU.) Num lock, scroll lock, and caps lock all still flash green almost immediately on power up, but, no beep, no video. That last includes trying the DVI outputs on both the MB and the monster graphics card, and, again, VGA and HDMI off the MB. (I’m still unable to find a speaker, but have not completely disassembled the front of the machine.) Having having become familiar with most of the rest of the layout of the machine back when and shortly after I originally created this thread, none of these rechecks and added checks took long. Maybe an hour at most. :-)
But, what the deuce is going on? The machine appears to have been in use perhaps literally the day my brother left home.
The only suspicion I have left is that combination keyboard / mouse connection on the back. Is it possible the machine “thinks” there is no keyboard if just a standard keyboard is plugged in there? Could I possibly do something by connecting a keyboard to the MB in some other way? Would the MB manual state that somewhere? It sounds “crazy” that this could be the problem, but...
Haha, I’ve done the same or similar (scouring the internet for identical PCs as backups). Or even just similar machine with full length slots for audio testing h’ware / s’ware packages...