Yes, but they have corrupted the searching for the question, not for the answer. The ultimate answer 42 has been calculated by Deep Thought long before The Earth was created.
You're right, I got confused. It's been a long time since I read the books.
Deep Thought required Organic SuperComputer Earth to calculate the Ultimate Question, because it was unable to calculate it on its own. But since the Golgafrinchan's fucked it up, the question itself was corrupted. And all was for naught.