BusinessWeek has an article about the change of OS from OS2 to Windows in ATMs:
Alliance & Leicester's head of the ATM business unit Wendy Luczwyco is one of many tasked with the migration from OS2 to a Windows platform. "It's a very big project requiring a lot of resource, not only from the IT department but throughout the whole business. OS2 is a stable operating system and we've never had any significant issues with it, whereas Windows will require greater management," she said.
The full article can be found at BusinessWeek.