which virus attaches to non-server machines?

Most of the new ones. Nimda and Code Red, for example, have multiple delivery methods. It's the "latest fad" in viruses. Nimda, for example, spreads through e-mail, open file shares, certain exploits in the Windows file sharing mechanisim, and a couple of different ways via IIS.

I would assume that Laura was being attacked by a virus looking for a server. The lines that point to WinNT appear that way...

Just because the virus is looking for an IIS server on which to install itself, doesn't mean it has to be running on an IIS box in order to launch the attack. That's why these newer viruses are such a bitch to get rid of, they try multiple simultaneous infection methods from any box on which they're launched.