What is the diffrence between a restraining order and a proctective order?

How do you go about it and what is the cost in Texas to do this? Regarding a ex girlfriend of son who is threatning to kill him and she texed his best friend and said for him to tell my son this and he saved it ..can this be used against her if we have a Sheriff's report already with a case number on her for coming over to our house with her lover (I warned my son that she was no good) and she tried to get in our home a few days ago by forcing her way inside then a scuffle ensued. Will u please explain what again is better or what ...do we need her address and make of car ect...birthday WHAT?? This is not a good thing...she is very out of it and on weird and dramaville..she stops at nothing and has been nothing but trouble and calls here 30 times a day. She is 20 years old ...not a minor, we believe she is a druggie and he wants nothing to do with her anymore! She called 15 times last night till 3 am or so and wont stop harrasing us. Someone shed some light on this please...