< Watching the browser's important. I hate to tell you, though--my sister's reasonably sharp for a civilian, and she swears she never OKed any download. I believe her, and so I fear this thing found some other avenue into her computer.

My understanding is that the .exe file is somehow automaticly downloaded. It assumes control in the .reg and settings area.
I understand it almost requires a reformat and reload.
Or at least extensive tweakui work.

As far as your comment on keystroke monitors, true, and I would wager that method of slipping them into the system is close to the same as the "900" programs.