Ok so here's the situation... I was waiting for a computer in the computer room at university, and this girl told me this comptuer that looked fine actually had a mouse that doesn't work... anyway next she got a computer before me... and here's the funny thing I don't know her but she was smiling at me when she saw me waiting for a computer there... and I am honest that I don't know her.. this is like the first time I've met her..! And she started smiling at me and waving... as if she knew me but honestly she doesn't and I don't know her... what does this mean??

Who knows?? Maybe she is super friendly and waves to people all the time.

Maybe she was so attracted to you that she just wanted you so badly she couldn't stop looking and smiling at you.

Maybe she is an axe murderer and that is her way of informing her next target that by midday tomorrow they will be mince meat.

Not sure what it means but next time you see her go and say hi and introduce yourself. You have nothing to lose. Unless of course she has an axe in her hand. :)