[b]Description[/b]
Win32/Sinteri is a family of e-mail spamming trojans. They also have the ability to update themselves.
Since avast is primarily an anti-virus program and this wouldn’t be classed as a virus in the true sense. However, if you send samples to avast (if you still have them) then I’m sure they would add this trojan.
If you are not getting a virus warning that you believe is a new, undetected virus, then if you can zip and password protect (‘virus’, will do) the suspect file and send it to virus @ avast.com (no spaces), or send from the chest.
Give a brief outline of the problem (possibly a link to this thread), the fact that you believe it to be a either a new, undetected virus and include the password in the body of the email. Some info on the avast version and VPS number (see about avast {right click avast icon}) will also help.