New desktop low battery notice... finally failed after 1½ years. New battery doesnt fix, won't start

[SukieC]

First time posting...
Pavillion Gaming 690 was purchased for Christmas 2019 and performs great, but displayed a low battery message at startup since the very first time.  It was not realized this may be a warranty issue.  During April'21, computer's ability to start by pressing button became intermittent and quickly degraded to not working at all.
My husband, who works out of state, was here and replaced the battery (we didn't know it actually had one until then).  He also followed related postings and did a BIOS upgrade.  Computer appears to not recognize new battery, even though contacts were confirmed to be clean and battery voltage at 3vdc.  Wall power is disconnected when computer is not in use.  When husband left town, computer would start after wall current was supplied for 10-15 minutes, but now won't start at all even after wall power is on for hours.  He will be away for a few more weeks.
Since the problem was apparently there when received from the factory, is there any way HP can please help us fix this?  Many thanks.
Best,
SukieC

[itsmyname]

Does the computer start at all, when the power-cable is installed, AND the battery has been removed?

Some computers have a tiny battery on the motherboard, in addition to the large battery that powers the computer.

Is that tiny battery at fault?