I'm spending a big chunk of my time cleaning Trojans and HiJackers off my client's PCs. It's getting really bad especially for IE users. The stuff that replicates itself and hides in the registry is unbelievable. If you miss something, it'll just come right back.
JWinNC
That's why Linux is immune to scumware. It doesn't have a registry and doesn't leave programs lying around. If you uninstall something from Linux, its gone for good.