Shoutbox

1. Most likely as you said, it turned inactive.

2. If she never blocked you, you will be able to see her online regardless of her having you in her list. Sometimes people ignore the block checkmark that you find when you're about to delete someone.

3. As long as you're deleted from her list, she can not see your status. However, she can chat with you and see your status if she adds you again. Actually, she can chat with you even if she doesn't add you.

4. If you do send a message to her, she will get a notice saying "This person is not in your contact list." If you don't do anything, she'll probably never notice (unless she also opens the Tools > Options > Privacy > Contact list > See who..).

Simply said, she doesn't have you in her list, therefore she doesn't see your status, she probably doesn't even know that you have her in her list. Unless she opens the list and blocks you, you will be able to see her status.

PS: In my opinion, no matter what the case is, you should attempt to contact her again. There's no point in spying on her nick, status and PSM if you're not friends? If you can't communicate with her, I'd delete her (and block here).