Depending when you did this, it's possible you destroyed private keys to BTC. I always check any discarded computer I come across for that reason, before wiping.
If the computer was discarded, I wouldn't consider it stealing. However would I feel like I had a duty to return it to it's previous owner or heirs? It depends on the circumstances. I have not taken/stolen significant sums of money in the past for moral reasons.
I don't think your comment should have been downvoted as it is thought-provoking, but it might have been downvoted since I said "discarded", and thus taking it wouldn't be stealing.