Bill is absolutely correct. And since it is spoofing mudcat in it's message, it's pretty certain you already have something not-so-good going on in your system.

The IT folks at the university library where I work have us use a cocktail of free programs, Spybot Search & Destroy and Lavasoft's Ad-Aware to get rid of about 85-90% of the nasty stuff. They are best when used together.

SRS