a howto,
easy no.. all HP putes have a service manual
and all cover this, (not thin notebooks, they hide head in sand)
the COMPAQ is HP, for sure.
the question is where is it, well its on the mother board.
and can be top or bottom on all Laptops.
some are just hatch cover, access, did you try those first.
400 what, bottle caps, or dollars or Rupies? what?
lappy means you are not in USA but UK or down under or india.
we dont use that word here, notebooks now, or laptop.
this tells me what actions are possible for you , you never told country so cant really help can we, you posted to a CALIFonia from
and you dont have Geek squad do you, LOL !!!!!!
this PC is now officially obsolete.
HP calls that
RETIRED, I call it zero support and is that.
or LEGACY, means same, DEAD.
first what is there, only this.
https://support.hp.com/us-en/document/c00424053
we throw those away here in USA>
it has no value at all now. why not upgrade,
buy a pc with W7 on it, and win.spend cash on things worth cash.
this thing is not. but that is good advice, so now your answer
we use google here, to find relic books
lets do that now.
heads up , laptops can be very hard to service.
ever do one. simple as
hatch off
keyboard off
or total disassembly on some.
see?
on a desktop (hint get one) its always easy
google hits the 1st one, OMG 1st yes,
is your manual. free btw no scalpers pricing nor viruses hacks.
https://www.manualslib.com/products/Compaq-Armada-4220t-2342152.html
now to to the coin page. coin cell battery page.
pdf page 118
real page 5-30
it says open bottom memory hatch.
gee you did look there first> wow.