The cable that connects the display to the board has failed. Unlike the color versions of the TI-84, the display is held onto the calculator with a TAB (Tape automated bonding) connection that cannot be removed non-destructively. You will need a TAB machine, new display (the cable will be damaged upon removal) and a lot of experience to get this right.
In addition, like the TI-84 Plus (also B&W), the board is held in with plastic - these need to be broken and fixed with screws in order to secure the board correctly again. Supposedly TI sells refurb calculators for $100 (they may want the bad one back), but it’s usually cheaper to get one from a high school/college student who only used it for 2-4 years (and took care of it and then forgot about it) or a bookstore who sells used TI calculators.
The TI-84 Plus (the one I own), the SE (yours) and the CSE (discontinued quickly) are all equally as disposable.