I vaguelly remember around this time some low end computers were shipped with FreeDOS instead of Windows, in order to save on licencing fees. AFAIK this was the case because legislation in some european countries restricted the sale of new computers to ones which had an OS preinstalled.
Maybe XP was installed after the purchases however a partition with FreeDOS/whatever remained as the default boot option. Hence your parents had to select the other boot option (Windows XP) manually. Granted you could change your primary boot partition permanently, but maybe your parents didn’t know this.
Tatsächlich ist abgelenkt wirken (aber nicht sein) ein guter Weg Autofahrer dazu zu bringen, tatsächlich an Schutzwegen stehen zu bleiben. Ansonsten sind diese ja leider nur für viele ein Vorschlag.