If you found out that somebody that you considered a friend and let use your computer posted under your TER account with aliases?  Rest assured I wont let her use my computer again, and I want to approach her about it  but I have no proof that it was her.
  What would you do?

Thanks!

YOU BIG DUMMY!!!  Don't you know that all women are natural snoops? I bet you take your wallet with you when you go on "dates".

Why would you let your browser sign you into ANY online service automatically?! Bad! Bad! Bad! Bad! Bad! Bad! Bad! Bad! Bad! Bad! Bad! Bad!

Don't forget, if you remember the date/time she had access, you can always check the browser history to see if it was her.

You can't sweat it if you have no proof. If she only posted under your aliases, there probably wasn't any damage done. The question is why she would have done this?