What is the infected file name, where was it found e.g. (C:\windows\system32\infected-file-name.xxx) ?
Check the avast! Log Viewer (right click the avast 'a' icon), Warning section, this contains information on all avast detections.
Or possibly easier, using note pad open the C:\Program Files\Alwil Software\Avast4\DATA\log\Warning.log file and copy and paste the contents here.
You have done the right thing, 'first do no harm' don't delete, send virus to the chest and investigate.
There is no rush to delete anything from the chest, a protected area where it can do no harm. Anything that you send to the chest you should leave there for a few weeks. If after that time you have suffered no adverse effects from moving these to the chest, scan them again (inside the chest) and if they are still detected as viruses, delete them.
I would suggest you remove your email address unless you particularly like spam. The forums are publicly available and could be trawled by bot collecting email addresses. You should be notified by email of replies to your posts, if you left the profile settings at their defaults.