How can a TA help a student who is certain she sucks at programming? I am a TA for an undergraduate Signals and Systems class (Electrical Engineering). As part of this, I lead a lab session, where we teach students how to code up various signal transforming operations in MATLAB, and visualize the transformed signals (for example, time-scaling, time-shifting, etc). So far it has been just basic stuff (it's only week 3), but the complexity will scale up quite a bit. 

One of my students has some kind of "code-fright". She understands the theory (because there's a pre-lab in which you write down the theory of what you will be coding in the lab, and she does well here), but when it comes to coding, she just can't get started; her editor is blank till the very end, and she doesn't ask for help when I go to her; eventually, she's on the verge of tears, and is clearly very, very upset. 

When I try to talk to her about what the code should look like, asking questions, and trying to get her to answer, she just remains stuck on the line, "I'm not good at programming". I repeatedly tell her that she has the theory down, and she simply needs to write it up in MATLAB, and reassure her gently that she can do this. But it doesn't help at all. 

How do I help her out? The lab has 20 students, so as much as I wish, I can't spend more time with her. But I don't want her to forever think that "she sucks at programming". 

EDIT - I forgot to add, this lab has teams. But she refuses to work with her partner (presumably because she wants to be able to do it on her own?). The partner does manage to get her code to work on her own.
When you tell her that she doesn't suck at programming, all she hears is that you don't understand how bad she sucks.  The psychology is the important thing here, not pedagogy.  If I were in your situation, I would say something like, "Yes, you do suck at programming.  In fact, most of us suck at programming. (Heck, have you ever noticed that Windows doesn't work???) But by doing some of these exercises, we get a bit better at programming.  Likely, you'll never be World's Greatest Programmer, or even a programmer, but by struggling, even unsuccessfully, with some of these exercises, you'll make yourself a stronger thinker.  And therefore a better person."  

I've gotten a lot more mileage out of "We all suck, so let's do what we can" than pretending that everyone's a genius.