Question PC won't boot after removing cmos battery

[Kandav34]

so my friend has a kinda old pc with these specs
i5 4590
biostar h81 motherboard
gtx 1060 6g
PSU spirit of gamer 600w ( doesn't have a back off and on switch)
he wanted to upgrade the ram from 8gb 4+4 to 8+8 16gb but the new ram didn't work and it did beep 4 times and then the system shuts down but works after trying the old ram again
however we thought removing the cmos battery for around 10-20min to reset bios settings would possibly solve the issue but after doing so the pc won't turn on, in the first attempt the cpu fan spins for half a second then stops with no signal even after many attempts
btw the psu has green light that stays on for a few seconds when unplugging it from the wall so we suspect it's an electricity that stayed in the mobo while we were removing the cmos battery
is the mobo dead or is there any troubleshooting we can do to revive it? I appreciate any help

 

[Yeaboyyyyyy]

You just make the bios is corrupted if your pc is from HP you can use the recovery bios

 

[Kandav34]

You just make the bios is corrupted if your pc is from HP you can use the recovery bios

the mobo is an h81 from biostar and what we did was just removing the cmos battery for around 20min but now it doesn't post anything at all, even the cpu and psu fans are not spinning but I'm pretty sure nothing wrong with the psu