Transferring data from hard drive?

This is a follow up to this question:

A) Will plugging a hard drive that I thought was dead into a new computer really work? Everyone is telling me it will, but I don't really understand why it will work since my old laptop didn't turn on at all.

B) My old laptop was a Samsung NP530U4B, what kind of hard drive is that so I know what cord to get?

C) Excuse me if this is an idiotic question. I THINK my old laptop had antivirus software, but in all my four years of having it I don't think I ever scanned it for malware once. Seeing as I've had this new laptop for a month and have already deleted over 200 pieces of malware, wouldn't that mean there would be hundreds upon hundreds of viruses on my old laptop? And… If I plug that hard drive into my new computer could those get transferred?

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