One of the first things that's going to happen when you start programming in asm are crashes. Some bug in your program will cause an infinite loop or mess up the stack and your TI86 will stop responding to keypresses. Don't panic! This happens to everyone. You probably have a GraphLink or some other way of transfering data to and from your TI86 so the stuff you have on it aren't the last copies. There's probably backups on the computer.
There are a few procedures to try when this happens. If one doesn't work, go to the next.
Remember not to panic when this happens. I know it's frustrating, it happens to me every day it seems. Keep trying and good luck. Don't quit!