If you're trying to boot from the old HDD then it's clearly something wrong with the OS/setup on that drive. Simply don't boot from it until you've formatted it/fixed it.
If that's not the case then just try removing the HDD again and see if the problem goes away. If it does, it's a bizarre hardware issue Ive never come across or heard of.
If it's still doing it after removing the old HDD then odds are you've transferred some virus/malware from one PC to another. Time to run a bunch of AV software.