I would actually say that Ctrl+Alt+Del was better known in mid-90s simply because so many people were still on DOS, and that was the proper and documented way to reboot it. Which was not uncommon to do especially since if a DOS app locked up, your entire OS was unusable.
I should probably clarify that I meant "known" by average consumers you'd see in a retail shopping mall, most of which at that point in their life have never owned or possibly even used a PC.
