[vr3690]

> it being on almost every windows pc

Every PC with Windows 10. I'm not sure how many there are, but it may not be most widespread or most used.

[scholia]

Windows 10 is probably on roughly 14%-15% of Windows PCs, which is some way short of "every".

According to Microsoft, more than 270 million devices run Windows 10. However, Cortana voice isn't supported in all countries, and many people have turned "her" off.