The W32.Swen virus which purports to be an email from microsoft, has taken off like a rocket just in the last 48 hours. It seems that huge publicity over previous email worms has not yet taught windows users to NEVER run an attachment (unless you requested one, from a completely trusted source), and not to use an email client that defaults to showing pretty HTML, instead of plain text messages. Security forum topic and some of the many news articles.

Interestingly, the virus also hits one of those web 'unique visitor' type counters, (see this post) and as of early morning the counter was at 615k hits.

it looks like the easiest REMOVAL tool is here bitdefender Swen page. (download and run removal tool from the link at the bottom of the page after the long description of what the virus does).