I'm assuming you removed the cables you reseated, and you are still getting the 5 audible beeps.
You can follow the below list of items you can remove, and between each bullet, try to start up the computer to see if it either boots, or if it starts giving a different audible sound. If powering on the computer ends up giving a different result, connect the computer to a monitor or display to see if there is any message that displays on the screen. Otherwise, start adding the items back one by one, but try booting up the computer every time you add a new connection to the motherboard. As soon as the original error comes back, you can conclude that that connection or hardware is faulty. Keep us updated when this happens.
Please ask questions if you are unsure about removing a certain item.
I would also work in a humid workplace and be on hard ground, remove socks, to make sure that you don't produce static. If you have an anti static band, you can use that. Otherwise, touch a plugged-in power supply every so often to remove static.
You can also check for any physically damage to the motherboard before you start.
- Power down the computer, remove any USB connections and other external connections, including the monitor. The only cord that should be plugged into the computer is the cord for the power supply. Power on the computer. If same error, then continue.
- Power down the computer, remove the cable that is connecting the CD-ROM to the motherboard, and remove the cable that is connecting the hard drive to the motherboard. Power on the computer. If same error, then continue.
- Power down the computer, if you have any M.2 drives, you can remove those. You did not specifiy the generation of your computer, so if you have an older computer, then the motherboard did not come with any M.2 slots, but if it is newer, then is should have some M.2 slots, and if it did come with M.2 slots, I'm unsure if they are populated. You can go to Google images and look up "M.2 SSD Drive on motherboard" or just "M.2 SSD Drive" to see what it looks like if you don't know. For this, you can manually (with your hand) unscrew the plastic thing that is holding down the drive, and it will pop up. You can then pull it out. When you reinsert it, check the pins to make sure that you are inserting it the right way. Also make sure the angle is low. You may need to wiggle it in. Don't apply too much force. When you remove it, power on the computer. If same error, then continue.
- Power down the computer, remove a stick of RAM (assuming you have two). Power on the computer. If same error, then continue. You can move the different sticks of RAM if you would like or try the other stick, but as you have already down that, it's not necessary, and you can do that again later.
The next three bullets can be done in any order depending on the ease of access to these parts.
- Power down the computer, remove any internal cables that are not needed. The only internal cables that should stay attached to the motherboard are the cables connecting it to the power supply, and the cable the connects the power button to the motherboard for (at least for now).
- Power down the computer, remove the graphics card. Note, that you shouldn't be using any force when removing this item. There is usually a lever on the slot like with the RAM that you can push down to make the card lose. Also make sure that you are unscrewing anything that connects the card to the computer case. Power on the computer. If same error, then continue.
- Power down the computer, remove any other cards connected to any PCI slots, if you even have any. Note, that you shouldn't be using any force when removing this item. There is usually a lever on the slot like with the RAM that you can push down to make the card lose. Also make sure that you are unscrewing anything that connects the card to the computer case. Power on the computer. If same error, then continue.
At that point, you may want to try a different RAM stick in a different slot just in case. You can also visibly check for any noticeable physical damage and let us know if you see something that doesn't look right.
- Power down the computer, remove the cable that connects the power button to the motherboard. To start the computer, you can use a screwdriver and simply touch the middle pins to start it. Try touching another pin if it isn't starting. To turn off the computer, you can shut off the power supply and disconnect the cord. Wait like 30 seconds to a minute after doing that before reconnecting the cable.
======================================
If the computer starts, or it starts giving a different POST code (different number of audible sounds), let us know. You can start adding items one by one and start the computer after each new connection is added until you get the same fault as before. Once this happens, that would be the faulty part.
If the computer doesn't start, then you either need new RAM sticks, or a new motherboard. If you want to buy new RAM sticks then check which generation the computer is. HP made this product with four generations. The older generations only use DDR3 RAM while the newer ones support DDR4 RAM. DDR3 RAM may a cheap investment if you want to try if that resolves the issue, but if it doesn't, then the motherboard must have went faulty. I wouldn't be sure if you would want rather get a new computer at that point.
If the computer doesn't boot, then I'm also not sure if you want to call HP support and see if they reach the same agreement. It's good to have multiple eyes on this kind of situation.
Good luck
