Sometimes when couples break up, they just can't accept the fact
that they are all alone again because they are too used to having
each other. Human are just like that, always refuse to change to
adapt the environment. Tell her that 2 years relationship is
nothing if that guy doesn't know how to appreciate and treasure
her, then he wouldn't worth her love, but then I doubt all these
can enter her ears now. 
When they are attached, they tend to neglect their friends, so when
they are alone again, they will worry that whether their friends
will still be there for them again. As a friend, you will just have
to play your part by supporting her when she needs one. 
From my experience, your friend will just need some times by
herself to straighten out her thinking, as she is getting better,
try occupy her time with activities so that she wouldn't have time
to think of the past, and don't bother to introduce any new guys to
he cos its won't help her at the present stage. Some take days to
recover, some will take weeks and some may even take months or
years. Time can heal her wound
