Hello, my HP Prime is stuck in an infinite while loop, I made a program that asks you random math questions with 3 digit integers and I accidentally made an infinite loop pressing apps, home or escape doesn't solve the problem because it's either in a wait (I used the command wait 5) state or its asking input from the user, neither does turning the calculator off.
Pressing Prime's On key should interrupt any running program. If not, press and hold down the On key, then tap and release the Symb key. This should force a "warmstart" (AKA "reboot") which will harmlessly return control of the keyboard to you. Don't worry; it doesn't clear your programs or variables.
Hope this helps! Disclaimer: I don't work for HP. I'm just another happy HP calculator user.