If you can open a command window, you could run the VER command (there's also WINVER but that may not be present in embedded) -- 5.0x will be Win2000, 5.1x will be XP, 6.0x is Vista and 6.1x is Windows 7 (because that's how Microsoft rolls -- there's a full list here
). Odds are pretty good that it is 32bit XP embedded, as that was around for a long time and continues to persist (I've seen it in currently-in-use ATMs, kiosks, and PoS systems).
Typically the basic drivers don't need .NET just to print, it's all the utility crap that they shovel on you that needs that to run. What kind of printer are you trying to use?