am i being taken advantage of?

What is the right thing to do here?
I have a girl that I use to be close with that moved upstairs from me. We are on okay terms but not close. When she first moved in I gave her my wifi password & let her borrow movies day after day. (which I had to keep asking to get back).

Once she started using my wifi the connection slowed down ALOT. We also work together and her work computer has a ton of virus' since she downloads music and god only knows what else.

So I called the company and got a new modem because the connection was sooo slow. With that came a new password. She sent me a text today asking me for the new password. I do not want to give it to her. My boyfriend who I live with doesn't want me giving it to her either.

(just a side note- i was using her computer at work from time to time to do homework until I got a new laptop and I guess she didn't want me to use it and changed the password and never told me-it's not her personal computer it's the jobs, who is okay with me doing home work there).

she can afford internet-she is taking online classes so I feel sort of bad. and she can be really mean and nasty sometimes so i dont want to deal with that. and we work together.

i dont want to get a virus or have my speed slowed down.. or get in trouble for what she is downloading.

and i do **** for her and she is just rude and mean.

what do i do? and how do i do it?

Just tell her that having multiple users on your wifi slowed down the connection too much. It's a neutral, logical explaination that doesn't place any blame on her like saying "You use too much bandwidth." You are under no obligation to share your connection. Considering that you feel bad about not giving her the password, you may be suffering from "too nice syndrome" as well

Take care.