Question How to replace CMOS with no access to BIOS?

grole

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My PC hangs quite often at "loading operating system - disk error". So I figure the CMOS battery needs changing (it's 10 years old). Problem is, with Windows 10, I can no longer get into BIOS: it won't recognize me pressing delete. I can't get in using the windows method either, as it's not UEFI - the option doesn't even show up.

So if I replace the battery, my BIOS settings are reset, but I can't change them anymore. Any ideas?
(I know, I need a new PC... getting to that soon)
 
What are your system specs?

Normally an hardware error on the system disk means you're dumped into BIOS. But you might disconnect the disk anyway to see if it will.

And resetting CMOS....either by the pin short or pulling battery for a few minutes...might do the same thing. As well as allow the DEL key to work again.
 

grole

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It's a system from 2011, motherboard is the ga-870a-ud3 and I've not updated it.

I don't remember setting up any fast boot option, not can I find it in the manual. In any case, it doesn't make sense to me to have an option which effectively locks the BIOS and needs a reset. I therefore assumed it was windows 10.

However, i unplugged the system disk and I still can't get in.

I've had this error intermittently, even with the old system disk (both SATA SSD). But it wasn't very often so i thought nothing of it. Now it seems to be every other boot. Usually it boots after a hard shutdown and restart, or at least after the 2nd try. Just thought it might have something to do with the battery seeing as it's so old.
 

Eximo

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If you hold shift as you click shut down, Windows 10 should give you the option to get to the BIOS. That may only apply to UEFI computers though.

Could also be a sign of the board being on its way out. Maybe the SATA controller is starting to fail.

Always good to check your PSU voltages as well. If the PSU is 10 years old as well, that could be causing a lot of issues if 5V or 12V is not right.
 

ravin_29

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You might have a disk issue, however I am just commenting on possibly how to get into BIOS.
As per manual the key is Del. Do you have standard keyboard 101 or more keys? Is there Del on the Num pad as well in additional to the main keyboard buttons? Did you try both Del keys?
Is it a USB or PS/2 keyboard? If USB did you try plugging it to some other port?
If USB can you check if you can manage to get a PS/2 keyboard from somewhere? It may be hard to find it today in 2021 though.
 

grole

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If you hold shift as you click shut down, Windows 10 should give you the option to get to the BIOS. That may only apply to UEFI computers though.

Could also be a sign of the board being on its way out. Maybe the SATA controller is starting to fail.

Always good to check your PSU voltages as well. If the PSU is 10 years old as well, that could be causing a lot of issues if 5V or 12V is not right.
Well the PSU is admittedly even older, like 14 or 15 years. How do I check the voltages and what should I look for?

And yes I tried the shift trick but it seems to be only for UEFI as the option doesn't even show up.
 

grole

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You might have a disk issue, however I am just commenting on possibly how to get into BIOS.
As per manual the key is Del. Do you have standard keyboard 101 or more keys? Is there Del on the Num pad as well in additional to the main keyboard buttons? Did you try both Del keys?
Is it a USB or PS/2 keyboard? If USB did you try plugging it to some other port?
If USB can you check if you can manage to get a PS/2 keyboard from somewhere? It may be hard to find it today in 2021 though.
Ok, I'm an idiot. I forgot that the keyboard was plugged into a USB switch, along with the mouse, for the last year or so. I use the monitors and peripherals for my work computer during the day. Plugged the keyboard directly into the PC and of course it works. Thanks for the comments, that led me to remember that!

I'll see about replacing this setup soon anyway seeing as I'm up to speed right now after just building a gaming rig.
 
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Eximo

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Tools like Hardware Monitor can give you voltage information in Windows. The BIOS, now that you can get to it, also should have a PC Health section

12V should be at or above 12V, technically it can go down to 11.4 while still in spec, but not a good sign.
5V similar, can go down to 4.5 volts or so before there is a problem. Still, you want both to be near the proper values, and to not fluctuate too much under a heavy load.

But yes, 14-15 years is way beyond the life expectancy of a PSUs main capacitors.
 

grole

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Thanks for that. I installed HW monitor and I'm seeing min voltage of 12.09 and 4.97 respectively. So seems alright at the moment. But I'll watch it, and I won't re-use it for the next build, promised!

I know it's unrelated but I've had this machine (Phenom II X4 Black) overclocked to 3.6ghz for years now, which has been stable. I've only recently paid attention to temperatures so I can't say how it's been in the past, but even running a stress test using CPU-Z the CPU temp is below 40°. I've just notched it up to 3.82ghz and still it maxes out at 41°. Compared to my new 5600X build which goes up to 70° under load, this seems low. Or is that a normal "high" temp for this CPU? The cooler is a Scythe Mugen.
 

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