When you can do it entirely in Swedish, without speaking a word of Swedish.
A friend (Swedish, obviously) came to me last week asking for assistance with their laptop. She said it wouldn't boot. I was hoping it'd be an easy fix, so I went to sort it out. It quickly transpired (chkdsk took 30 minutes to get to 3% complete... and this WASN'T a surface scan) that the hard drive was McBroken.
Seatools confirmed this, finding hundreds of dodgy sectors. Cut a long story short, I took the laptop away with me and ran the flaming awesome Damn Small Linux on it. I recovered to a USB hard drive the folders I'd been instructed to, prior to trying to fix the drive with Seatools.
Got 99% of of the files wanted (took a LONG time though), but Seatools couldn't fix it.
Yay, new drive time! Doubled the capacity in the process, but also had to install Windows XP, in Swedish. As you'd expect, all the buttons are in the same place, so if you've done it quite a few times before, it's a piece of cake, save the keyboard, because the crazy Swedish people have certain special character keys in different places.
Still, at least it works. I just hope the hard drive doesn't die on the laptop of any Chinese friends...