I'm sitting at a cafe, using their public Wifi. I don't go on sensitive sites; I basically go to a music site and listen to a live stream for which there's no login. I don't check my email or visit any password protected site. Some rare times, I visit stackoverflow, for which I'm automatically logged in. I'm using Windows 7 64bit with AVG Internet Security

1) Can someone hack into my computer and see/download my files?

2) Is there anything risky about what I'm doing?

Thanks.