There is no point in deleteing anything except for the bounced email. It is possible that someone is just abusing your email address, which they may have found somewhere on the internet. If that is all that's occurred, then after a while they get bored and stop expecially if no one responds to these emails. The first you get to hear of it is when they send to an email address which does not exist and so you get a bounce back. If they have got access to your contact list, there is no point in you deleteing it because it's too late. Suggest you start your computer in Safe Mode with Networking and run full scans just to rule out that no one is using keylogging or other crap on your computer. Also suggest you try Malwarebytes. * http://answers.microsoft.com/en-us/windows/forum/windows_vista-security/how-to-detect-if-a-keylogger-is-installed/d14c6cd6-6975-4b25-a2c5-17e5de194b50 If virus/malware was found to be leaking info, fix first and when you are certain that all is clear, Start in normal mode and update your passwords. If nothing was found then no worries; all is good. Suggest that you make sure you have a unique signature that can easilly be used to identify to the recipient that the email really was from you. This occurred to me a couple of years ago. I sent emails to all my family and friends, informing them that someone had been abusing my email address. I asked them - if you have received one of those emails, do not to click on anything or respond as this would only confirm that the email address was 'live' and could cause them other issues. I also informed them that from now onwards there would be a specific signature in all my emails, so that they would know it is was me.