A small title loan insurance office had just moved to a new building. The manager had been reading some PC magazines for a few weeks, and decided that she knew everything she needed to know about setting up a network of 5 systems and the Internet. She went out to Sams Club and bought 5 computers at $350 each (including 15" monitors), and had the Internet installed on site. Within 4 hours every computer was completely infected with all sorts of malware. When I arrived on the scene, after just one look at one of the computers, and the fact that they had a cable modem and public static IP addresses on each computer, I told her that the only way to guarantee that the computers would be "clean" would be to a) buy a firewall/router and b) that each computer needed to be wiped and had the OS completely reloaded, staring over from scratch. She insisted that I try cleaning her computer, since it had something on it she wanted, so I estimated that it would take at least a 3 hours at $75 an hour to recover her data. And that I'd be happy to show they how to reload their workstations.
She actually decided that it would be cheaper and faster to just give those 5 systems to charity and buy another 5 computers from Sams Club!
Mark
I've had clients make that decision as well.