Dream Machine

[snootmagruder]

Help! I got a new computer for my son and he wanted to download the harddrive from the old one. So I removed the old one and hooked him up to his new computer via a hard drive dock which he says went well and nothing to comment on, however now the old computer after reinstalling the HD won't boot. Seems as if a HD failure? The reinstalling is so simple I don't see how it could be wrong. Any tips to diagnose the problem?