I came across the post because I Googled the website.
I received this same email from an old friend who also had an earthlink address - I don't think she uses it any more.
Since the OPs email is hosted and not POPped, my gut says Earthlink has been hacked and the hackers are using user names and passwords from there.
It could well be that your computer is fine - just the hosted email server has been culled.