Something to wake you up if you're having trouble doing so, from The Wikipedias this time.
ATM vendors NCR Corporation and Diebold Incorporated have both adopted Microsoft Windows XP as their migration path from OS/2.
Diebold Incorporated initially shipped XP Embedded Edition exclusively, but following extensive pressure from customer banks to support a common OS, switched to XP Professional to match their primary competitor NCR Corporation
Personally I'd rather hear people say ATM Machine and PIN Number a million times each than use one with Windows on it. I guess I shouldn't be surprised, but it doesn't make it any less blood chillingly scary. It's also worrying that banks were complicit in and actually pressured ATM hardware manufacturers to adopt these operating systems; these are the institutions that are responsible for looking after our money.
It also doesn't make much sense, how many solid, reliable and secure embedded OSs are there and they're running a consumer operating system? That's like installing Vista on a car's onboard computer!