Scenario: Desktop system that's been running linux for about a year, with an oft-ignored WinXP NTFS partition on it for those rare Windows-only tasks.
Problem: So oft-ignored, I've forgotten my XP login password.
Solution: A number of options exist, but I was looking for a simple 'boot into linux partition and then hack such-and-such file'. Didn't find anything like that (and my old'ish linux install doesn't have write-to-NTFS support anyway), so I decided to try a boot CD solution, trusting that if source is provided it's probably not some trojan exploit thingamabob. First one I tried was Peter Nordahl's Offline NT Password & Registry Editor, cd070409.zip, which worked like a charm.
Sidenote: I then updated XP using Windows Update and the machine ground to a halt for a few hours, ultimately having to be shut off because it wouldn't shut down properly. Several reboots later it's working again, but that's pretty much standard for Windows. Gah.