Why wont my TI84 plus CE turn on at all?

Hmm, hopefully the answer is just you need to plug the cable into the USB port harder, or try a different cable. Can you try a different power source? ie instead of using the charger brick that came with the calculator, plug it into your laptop (or vice versa).

Can you turn on the calculator while it’s ‘charging’ using the [on] or ‘reset’ button (the reset button is located on the back of the calculator)? If so, (and the battery indicator in the top right is orange) I’ll bet it’s a battery issue. Have you tried replacing it or swapping your battery with someone elses? (You’ll need a small Phillips head screwdriver to take off the back) If you can’t turn it on, well, read the next paragraph.

I hope one of the above issues was your problem, however if it’s still not working, You can test if your USB port is broken by replacing the battery with a charged one, then connect your calculator to your computer, if your computer recognizes something was plugged in, then data transfer is still working and there may be a bad power connection somewhere between the USB port and the battery. If your computer doesn’t recognize that something was plugged in, then you have a more serious issue. You may want to refer to the TI 84 Plus CE recovery guide to help, although I don’t know if it’ll fix your situation.

I’m sorry I don’t have a fix for you if either of these are the case, you may need to either contact Texas Instruments support, or use your warranty (if it still applies) to get a replacement calculator.