Can't get system to boot

[cooltouch]

OK, here's the lowdown. A few days ago, I upgraded my Win7 PC to all new stuff. So, actually, except for the case, everything was replaced, even the power supply. New MoBo, processor, drives, RAM, keyboard and mouse.

I decided after setting up my Win10 system that I'd like to keep a Win7 system around for legacy hardware and software. So I took all the items I'd removed from the case and installed them in a spare ATX case. The MoBo, processor, drives, memory, and even the power supply were those that I'd removed from the case that now houses the Win10 system. So what I in effect did was just put the old Win7 system into another case. The only thing I presently don't have for the Win7 system is a keyboard and mouse.

Well, I decided after putting the Win7 system back together that I'd go ahead and at least see if I could get the system to post. And this is where I ran into a hitch. When I turn on the switch on the back of the power supply, the motherboard activates and goes through some sort of self test. bub before completing it, it shuts down. The power switch on the case doesn't do anything There's also power and reset buttons on the motherboard. These don't work either.

The motherboard is an ASRock 890GX Pro 3, using an AMD processor. Among its features is an LED next to the power and reset buttons on the motherboard that gives a readout during post. It stops at a code "4d" and stays there for a second or so before the system shuts down. So, I got out the manual and looked up 4d. The closest it gets to it is a range. The manual says "0x3F-0x4E" and " OEM post memory initialization codes". I'm interpreting this to mean that 3f to 4E are associated with this message, and that 4D is within this range. But I have no idea what " OEM post memory initialization codes" means, but it doesn't sound to me as if it's an error message. Soo maybe 4d doesn't mean anything detrimental. One can hope.

But then the question becomes, what might be causing this system to halt during post when, just a few days ago, it worked fine? I've been playing around with the motherboard power hook ups -- 20 or 24 pin, both work. And the other socket -- the ATX one? -- is an 8 pin socket but the manual says that a 4 pin connector will work. With this power supply I have a choice of two -- a 6 pin and a 4 pin. The 6-pin doesn't fit right anyway, so I just use the 4 pin. With the 4 pin inserted and either the 20 or 24 pin connecter hooked up, I get the halted boot sequence. If I disconnect the 4 pin and switch it on, the processor fan spins up and stays spinning, but the boot sequence on the motherboard's LED doesn't light up.

At this point, I'm wondering if not having a mouse or a keyboard hooked up might be causing the problem. I'm using wireless units that pick up their signal from a little dongle that plugs into a USB port. From my limited understanding of the way a PC works, I didn't think a PC even sees the USB bus until it's well into its boot sequence. I'm gonna try it though. I'll have to power this system (the Win10 one) down to do it. So I'll report back once I've tried it.

 

[cooltouch]

Well, I didn't think hooking up a keyboard and mouse would make a difference and I was right. It still does the same thing. Shutting down a few seconds into post.

This PC has 16 GB of DDR3 RAM, which I bought new a couple of years ago. Just for grins just now, I pulled 8 GB of it, then switched on the power switch at the power supply. This time the boot sequence lasted longer. It made it all the way to a code of "60" before shutting down. According to the manual, "60" is "DXE Core is started." Welll that's good, but it doesn't stay started.

Any ideas? I'm hoping I didn't ruin the motherboard. When I took it out of the case, I just laid it on top of some hand towels, then some other stuff gut piled on top of it -- paperwork, mostly. Nothing that would build up and generate a static discharge. And I don't have carpets in this room. Just wood floors. that are pretty scuffed up. This area has been my workstation area for the past 6 years and I've never once seen nor heard nor felt any static discharge in this area.

 

[Megahertz07]

Did you check the PS voltage setting switch?

Ok, so you put on the MB 8 pin CPU power connector the a 4 pin PS connector. Did you checked if the yellow (+12V) and the black (0V) are on the right place?

Did you removed the CPU and the heat sink from the MB?
Did you try to reset BIOS removing the CR2032 battery?

 

[cooltouch]

I didn't change anything on the power supply. So the voltage is still the same.

That 4-pin connector installs into the 8-pin socket only one way. But yeah, I double checked with the owner's manual anyway, and it's installed correctly.

I didn't remove the CPU or its heat sink.

I did NOT try resetting the BIOS. I mean, what changed? Nothing. But I'll give that a try anyway.

OK, I just reset the BIOS. No difference. It still stops at the same point.