Do you know of any tools I can run regularly on my Windows NT 4.0 Web servers to detect and delete spyware files?

Spyware is a new type of malicious mobile code that Internet browsers transparently download to a machine's hard disk (typically as part of an advertising campaign linked to an Internet Web site). The spyware can then monitor a user's activities and report findings to an Internet host. Lavasoft's Ad-aware, which Figure 3 shows, is a freeware utility that lets you scan system memory, the registry, and all disks for spyware files, then remove the malicious files. Ad-aware uses a scanning process that's similar to the technique that antivirus products use; it requires an up-to-date signature file. You can download up-to-date signature files from the Lavasoft Web site at http://www.lavasoftusa.com/downloads.html (click the Ad-aware signature file option). You can also purchase the Ad-aware Plus add-on, which provides unlimited free product upgrades and support and a realtime spyware-protection extension.