I have a 21.5 inch iMac EMC 2544 (late 2012) that had a bad logic board. Well i replaced the logic board, replaced the old...

It is likely if you used a metal item to clear the charging port you broke one of more of the gold connection pins which could have shorted out the charging port. Try using a different cable, different power brick, or a different outlet and see if the results change. Maybe leave it over night if you aren’t too worried about it being shorted out. If the charging symbol goes away after a few seconds that’s pretty normal. Try clicking or holding the power button on your iPhone to see if you get the low battery symbol to populate if not and no sign of life is shown then it is very likely the charging port has shorted out and will neeed to be replaced.

You need to replace the battery. If you click on the apple logo on the top left, then click "ABOUT MAC" then Select the "SYSTEM REPORT" you will find a description for power on the left hand side and that will take you to the battery information if there is no information the battery has gone bad or may be disconnected all together from being dropped or some other related type of incident. You can check the connection of the battery by opening the bottom of the laptop and checking the connection of the battery to the logic board on the inside. If you are not familiar with the process, i would recommend taking it to an authorized apple repair center to have them take a look at it.

If no sound is produced or there is no sign of life check the LED signs of the Logic Board. From there you should be able to check the light indicators on the logic board itself and see what exactly is going on. If the first LED is lit up then that means that the computer is receiving power but is not processing it properly and is either a bad power supply ( knowing that you replaced it recently it could still be bad, just maybe a faulty one was sent to you, rare but it does happen unfortunately) or a bad Logic board itself. IF you have any other questions just ask!

Depending on the laptop if it was purchased new or used, the OS on it usually can contain a bunch of junk files that are corrupted and bogging your machine down. Backing up any important files and saving them on an external drive is crucial. You will want to save all you can then preform a clean install of the operating system. 4GB of RAM is plenty depending on how many programs you want to run at once. If you are only using chrome and maybe word at the same time then you are fine. Unless you are gaming and running an OBS capture system with chrome open along side discord or any other chat based system then you will want to upgrade your RAM. But if you PC is slow in general like I said if it is used then a clean install of the OS is what you need. Even if the person preformed a factory reset of the computer. That person old registry settings and keys are still in the system. Deleting every partition on the HD or SSD and clean installing the OS is going to give you the best result.