Hi there again,
I ran again the usb boot memtest and, just before the 2nd pass finished, it displayed 24 errors. Here is the image that I took of the event:
I read that the next steps are to check if the ram sticks are in the right motherboard slots. Also, to check the different sticks with the memtest, but the problem is that am new dealing with these kind of problems. I like to know if there are any tutorials or videos for best practices or if it's recomendable to take the laptop to a technician. Any advice would be welcomed.