Should I be worried?

So I logged on to my yahoo mail to find that I had over 300 messages all by one e-mail address and each with message body saying just "12". But then I saw an e-mail from blizzard that my password for my battlenet account for WoW was changed. I changed it back and ran mbam and avira's scan. They both found nothing. However, a week ago I did run Avira and found a java virus and got rid of it. I'm currently running an eset scan just in case. Should I use your Read and run guide? or is this just some spammer I shouldn't worry about?

Thanks!

 

eset found nothing