Weird phenomenon of desktop booting need help

[Sparker03]

@TheOldMan.  I don't mind trying Ubunto again,  but Ubuntu is the same thing as pi Desktop, the result will be expected to be the same.  I give up pi Desktop because I suspect BIOS corrupted. Here is my thought:

1. the Hard drive was not seen by pi Desktop when it was booted from USB is because the corrupted BIOS did not register the Harddrive as an available device to the newly started pi Desktop OS device manager. 

2. Why I can boot into windows by resetting CMOS with corrupted BIOS?   I assume the BIOS was designed in this way:  whenever CMOS data checksum is wrong, it will allow entering BIOS utility interface for date and time setting, then bypassing or omitting the hard drive and other devices registration, then handover to bootloader for OS booting, since the hard drive was registered before in bootloader, so Windows get booted.

3. When CMOS was not reset, the corrupted BIOS will stack somewhere and never hand over to the bootloader, therefore a black screen occurred. 

A new phenomenon is, Now even I reset the CMOS, the black screen occurs often, it won't guarantee entering into BIOS utility every time,  

[itsmyname]

@Sparker03 --  if I don't reset the CMOS, it will always boot into the black screen no matter how long the machine was shut down before.  

This could be "corruption" of the stored settings inside the CMOS.  Maybe, caused by a failing CMOS battery.

When you reset the CMOS, the motherboard does a complete inventory of the hardware, and writes the values into the CMOS, and your computer loads Windows, and runs. After a shutdown, the next power-on event reads "corrupted" values from the CMOS, and you get the "black-screen".

[itsmyname]

@Sparker03 -- A new phenomenon is, Now even I reset the CMOS, the black screen occurs often, it won't guarantee entering into BIOS utility every time

It may be time to schedule a "funeral" for your motherboard. It is showing more & more signs of terminal failure, despite your attempts at advanced life-support.  

R.I.P.

[Sparker03]

@Itsmyname.   the CMOS battery is new,  I bought it a month ago.  it is 3.12V measured by a multimeter. 

Well, to scrap a machine is an easy way, but it gives nothing to people coming here.

[TheOldMan]

It is getting more curious with this PC.  If you had the battery out, in your effort to reset the CMOS, did you also set the BIOS back to default and save the configuration? 

[Sparker03]

I don't know how exactly pc boot-up detailed procedure is, how CMOS data is used and reset by BIOS.....unfortunately, these information are hidden from vendor to vendor.   Everybody in the industry wants consumers to scrap existing machine and buy a new one except consumers themselves even though the machine hardware is still working.

I am trying to save this machine because its hardware condition is still good and fast enough for jobs like checking email, browsing on the internet etc.  It had been upgraded to 6G memory to cater to Windows 10.

[TheOldMan]

You can get into the BIOS to check and reset to default.

Start tapping the Esc key BEFORE starting the PC and then press the start button.
Keep tapping the Esc key until a popup menu shows.  Pick F10, check various settings including setting to default settings.  Save and the exit.  Be sure to save before exit.

[itsmyname]

@Sparker03 --   it is 3.12V measured by a multimeter

When you set your multimeter to "amperage", what value do you see, both in the removed battery and in the brand-new battery?

I can show you AAA batteries that (chemically) still generate 1.5 V (as per its specifications) but the measured amperage is less than 10% of the original (5 amperes). Compare to one person trying to carry a coffin to having six persons carrying the same coffin.  The battery's chemistry still generates the 1.5 Volts, but there are insufficient simultaneous chemical reactions to generate even 10% of the original amperage.

[itsmyname]

@Sparker03 --  Everybody in the industry wants consumers to scrap existing machine and buy a new one except consumers themselves even though the machine hardware is still working.

You wrote that your desktop is 8 years old machine.

I had a 2001-vintage Ford Taurus that I "scrapped" in 2014, for several reasons:

* the motor in the sun-roof broke,

* the passenger-side door would not lock (mechanically nor electronically),

* it would have cost nearly $1000 to replace, balance, and mount replacements for the 4 bald tires,

* the "book value" of it was around $4000, but the local Ford dealer offered only $1300 as a trade-in,

* its 6-cylinder engine was a gas-guzzler, even though it I liked that it had lots of horsepower,

* other "worn-out" components.

It was time for it to "go".

Although your eight-year-old computer is "mostly-working", it's time to consider responsively recycling it at an "end-of-life" processing centre, when new computers, with Windows 11 pre-installed become available, probably by XMAS 2021.  Amortize its cost over the last eight years, to show that you have gotten good value for your investment. Your next computer should last for eight years.

Is the disk-drive also eight years old? That is "antique" -- if you keep using your computer, consider upgrading to a SSD, for better reliability and more speed.

[TheOldMan]

I think it might be time to consider what @itsmyname says at least about the hard drive  "Is the disk-drive also eight years old? That is "antique" -- if you keep using your computer, consider upgrading to a SSD, for better reliability and more speed."

If you have done the BIOS reset to defaults and it still does not work, then try a new hard drive or SSD.  They are relatively inexpensive and if that does not fix anything/everything it can be used on other PC's.