I think you should not scan the recycle bin by default. It causes grief for two reasons.
1. As Avast finds viruses, I remember all the hundreds of email spam attachments. I start to put them in the trash. Avasti finds them again!
2. I can't empty the recycle bin, because Avasti is holding onto a file it has found there with a virus.
I am using the home edition. I am not sure what version it is. It updates it self regularly. It does not appear to have an about box.