I have an iPhone 8 that would not be detected by computer

Thank you so much for the response. I went ahead and tested a new charging port and the phone boot up and worked. So I replaced, powered on the phone before closing the screen. Phone worked great, when I closed the screen back in place, it won't come on. So I opened it again, checked every connections and the screen came on. After this I closed back the screen and it refused to come on. So now I'm stuck on what to do.

Why does it work when screen is opened and then refused to work when screen is put together.

@akinlolu Is the back plate secured to the screen? In my experience this commonly happens when the back plate is not moved across during a screen replacement, and the display and touch cables are caught between the screen and frame, preventing the screen from functioning until the pressure on the cables is released(opening device back up). Ensure that the back plate is secured correctly and the display and touch cables from the screen aren't being mushed around or squished when you're putting the screen back down!

the only known and tried method in such cases is to return to the previous state. Take out the new tape and close the phone without it. Before that, however, check what happens when you close a working phone (it works with an open screen - close it when it is turned on). Important question: when you close the screen and the phone won't turn on (with new tape, speaker and taptic engine installed) doesn't the phone turn on or the screen? Check if the phone vibrates, makes sounds. You can connect it to a computer and see it on its screen. This looks like an accessory problem (you may have damaged screen tapes or the grounding of the new charging port is faulty - it happens in Chinese parts)

I assume you didn't damage your electronics while removing the connectors from the motherboard