What a dilemma, huh?
How do you accidentally find a child porn website?
If it was an accidental intrusion, seems to me that would be a great defense, if you were later arrested.
However, if you found the child porn website by chance and lingered an hour, two hours, three hours, even 30 minutes; that might not be considered an accident.
I'm wondering, if it was an accident, why would you destroy a perfectly good computer?
Whatever you do, if you are arrested, make no statement.
Ask for a lawyer, or hire one on your own. Let your mouthpiece do the talking. Loose lips, sink ships.