Even if you have the option to park directly in the sun, would you?

Being in a car that has been heating up for several hours of direct sun exposure is grueling. Switching on the AC to cool down to acceptable temperatures will probably drain more battery then was gained by the solar panel.

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.