Computer users across Iowa are being warned to be on guard for a new incarnation of an old virus. The Melissa virus first spread around the world as an email chain letter in March of 1999. The new version can hit P-C and Macs and will forward itself on to the first 50 people in your address book. Dan Buda, of the Central Iowa Computer Users Group, says there’s one way good way to protect yourself — update your anti-virus software at least monthly, if not weekly. Buda says the subject line may say something like “An important message from..” and then someone’s name, along with an attachment and a text line reading “Here is that document you asked for. Don’t show it to anyone else.” The attached file may say “anniv.doc” or something like that. He says if you get this message, don’t open it. Delete it immediately, then empty your recycle bin.