If your legit Steam version forces a check:

In Bubble Bobble Hero 2, players take control of either Bub or Bob, two dinosaurs who are on a quest to save their girlfriends from the clutches of the evil Magician. The gameplay involves trapping enemies in bubbles and popping them to defeat them. The game features many of the same mechanics as the original, including the ability to create and pop bubbles to trap and defeat enemies.

You bought the game in 2014 on a physical CD-ROM. Your disc is scratched, or you no longer own a CD-ROM drive (since modern laptops omit them). You own the license, but the physical media is useless. A NoCD crack acts as a lifeboat for your legal purchase.