For some reason my login info doesn't work anymore. I'm absolutely sure that I'm entering the information correctly. What has happened?
I know what happened here. Most likely reason is:
You tried logging in with the wrong username.
I know that comment might anger you because you "know" that you typed everything correctly. But you should considered the possibility that you are wrong. Accounts don't generally just disappear, but users simply forgetting their IGN or password is
very common.
There
is probably a 0,01% chance that this was
not an error by your part and that your account
has in fact mysteriously disappeared (first case of this happening EVER as far as I know). If that's the case, then I'm sorry and I hope you get your account back.
You said "doesn't work", but specifically what kind of error are you getting?