Avast Virus warning messages in emails

[Concrete donkey]

I've been on holiday the last few weeks, my brother using the PC while I've been gone. A few days before I got back avast started popping up loads of suspecious message alerts from my Avast mail scanner

The full text is

avast! Virus warning
Suspicious Message!
There are too many identical e-mails in appointed time


Sender: (random address)
Recipient: (another random address)
<address>
Subject: (Random spam message)

They just keep popping up. No email programs are running at the time, and I don't recognise any of the addresses.

I did a google search and said something about bouncing emails but I have no idea what it actually is. Any help on how to stop this problem ?

[Pilotwings]

Usual story your bro's been checking out porn and scattered your email across the net.

[Concrete donkey]

Usual story your bro's been checking out porn and scattered your email across the net.

That's what I was thinking, or he ran a stray executable file. What I don't get though is that none of the emais are addressed or sent from me, and comes up when there's no email programs or windows running.

[Hohum]

Sounds like your brother has installed a virus or trojan on your system, and your PC is now firing off spam to other people.