If you don't have her Yahoo ID there is no way to block her viewing your answers that Yahoo provides.
I would like to give you a bit of wisdom.
If a woman is stalking you, in her mind, she believes there is a chance that she can learn something about you that would enhance your relationship together in a positive way.
You may have been TOO NICE, in your efforts to get her out of your life.
The BEST way to END a relationship 100 percent is to be 100 percent CLEAR that you do not want ANYTHING, not even "friendship" with her ever again.
Stalkers are so desperate, that if they can't stalk you one way they will find another venue. So it is wisest for you to contact her, and tell her in a VERY FIRM and "not nice" way, that you don't want any contact in any way shape or form.
Do not feel you "owe" an explanation. In fact tell her there IS NO way to explain or excuse...it's just the way you are certain that you feel. Tell her that for you OVER is OVER....that it does not mean "someday", and that there is no "hope" for her to hang onto. Then tell her that this is the last "Goodbye forever".
Yes, I know that seems harsh, and for most people totally unnecessary...but for this poor soul, it IS necessary.
^j^