I tried to upgrade my dad's computer by switching the ram module from 4gb to one with 8gb. I press the power button, the leds light up, then comes one short beep and there is nothing on the screen.
The computer is a HP ProOne 400 G1 All-in-One PC (link to all docs) with a (completely) broken display, so he uses the pc with a second monitor.
This is the ram: 8gb hyperx impact 1600mhz sodimm ddr3 (cl9). It has the same frequency and voltage than the original ram, only the cl is lower (9 vs 11). (This could be a problem?)
This is exactly what I did: I opened the computer, replaced the ram module and turned it back on. It didn't boot so I read online that I should have reseted the cmos before putting the new ram. So I took the new ram out, reseted the cmos and putted back on. Nothing. Then I putted the old ram back on and also nothing. (I tried the old ram on both slots). I tried a few more times and also removed the battery from the mobo instead of pressing the reset cmos button on some of the attempts.
First I thought that the beep could be a error message, but acording to the Maintenance & Service Manual, there is no error code with just one beep, so I think that maybe it's a normal sound? (My dad is 65 yo, he does not remember if the computer beeped on startup) And also there is no red light blinking (in contrast to what happens when I try booting with no ram modules, which gives me red light blinks and 5 beeps).
As the screen is broken, I'm not sure if it is possible to acess the bios because I don't know in what part of the startup the second monitor starts receving the image.
I'm reaching out to you guys to see if anyone has any ideia of what can be happening. What exactly happens when the reset cmos button is pressed? Or the battery removed from the mobo? Shouldn't the old ram module work?
(Nothing seems broken. Nothing smells burnt.)