To keep things straight: Hero Quest was a Milton Bradley board game (and later somewhat-buggy video game). Hero's Quest (So You Want To Be A Hero) was Sierra's workaround, but it was alas not around enough for MB's lawyers.

Like many others, this game offered a little rhyme to suggest some structure to the player:

Comes a Hero from the East
Free the man from in the beast
Bring the child from out the band
Drive the curser from the land

At the risk of some mild spoil, uh, -age, I'll somewhat deconstruct and elaborate upon this woefully misleading rhyme. Seems simple and straightforward enough, but remember that it lists ends, not means - you've got to do dozens of other sometimes-tedious, sometimes-hilarious little tasks, quests and puzzles to even approach completion of any of the above.

    Comes a Hero from the East
At the start of this game, you, the unnamed Hero, arrive fresh from courses offered by the Famous Adventurer's Correspondence School for Heroes in your hometown of Willowsby - presumably located somewhere to the east of the sleepy hamlet of Spielburg, past the avalanche-blocked "Only Road Out Of Spielburg."

    Free the man from in the beast
This, of course, refers to the Hero's reversal of the transformation of the Baronet Bernard von Spielburg into a bear by the Kobold wizard - a minor sub-quest as far as game completion goes, but what's news about members of the royal family is I guess news for everyone in the area.

    Bring the child from out the band
Another transformation of sorts to be undone here - but this time a social one rather than a physical one. After her kidnapping so many years ago Else von Spielburg grew up to actually become the leader of the band of brigands terrorizing the valley under Baba Yaga's curse. Splashing her with the Dispel potion turns her from a kick-ass, in-control female (not to be permitted in any traditional fantasy setting unless perhaps the leader of a tribe of lesbian Amazons who just need to find the right man) back to another hapless ditz. I swear, much of this conventional heroism is distinctly amoral!

    Drive the curser from the land
This line is interesting since, if I recall correctly, it is possible and even easy to finish the game without driving anything anywhere.
    "Unfortunately, since the Baron is still cursed, and Baba Yaga remains to work her evil deeds, terror will continue to rule the land."
What is supposed to happen is that after dispelling Elsa's curse, you snatch the enchanted magic mirror of reflection on her desk, traipse over to Baba Yaga's Hut and reflect the spell she casts at you back on her. However, if you fail to take the mirror while in the Brigand Leader's room, or even do take the mirror and stop at the castle en route to Baba Yaga's, the game (EGA version, at least) ends - award ceremony, magic carpet and everything! Don't these people mind that they're still under the curse of an evil Ogress? She pops up again in QFG4, having retreated there after having her spell backfire on her, so the game designers clearly intend for your hero to have vanquished her back in QFG1... but strangely they arranged things to make it possible to complete, seemingly victoriously, without resolving the final, and most important, quarter of the prophecy! The forgetful player might never understand how they managed to complete the game with such a low score.

My personal favourite theory about this line refers to Sierra's disastrous move from the winking cursor of its command-line-type interface to the genky mouse-driven games they shifted into producing after the amazing Quest for Glory 2. As with all prophetic lines, this one took a while to kick in...