Doesn't seem like that big a deal. I wouldn't be worried about screwing up your parent's credit card or whatever.
I think I know what fraud verification thingy your talking about. "Verified by Visa" is one of them. It just verifies the card by asking for a PIN when completing the transaction. If the order went through twice then you'll either get two CPUs, or if they get your e-mail, they'll cancel one of them.
The worst thing that could happen is that the credit card company puts a hold on that particular charge until the cardholder calls to verify the charges.
I got that when I ordered $1300 of computer hardware from newegg. I had only used the card for a gym membership and when they saw the $1300 charge the held that transaction until I verified the amount over the phone.
It's kinda nice actually, they do that with most large online purchases over $300 (if you don't do that regularly) to keep someone from illegally using your card.
I'm sure everything will be alright even if you have to drive an hour to get your CPU.