Your work PC should be locked down to disallow software that requires administrative privileges such as SADP, so not surprising it hangs.
Supplying 15v to a 12v camera may well cause damage. Hopefully it just shut down safely due to overvoltage. Best not to repeat.
12v 1A will be just fine.
What you haven't said is what type of network the devices are connected to. Best not to connect directly, use a switch or router so both ends can be active and not dependant on each other.
Assuming there is a router with DHCP active, first check if the DHCP server has issued an IP address.
If the camera does come up on the default 192.0.0.64 address, your Mac will also need to have an IP address on the same segment, such as 192.0.0.128. What did you use in your testing?
You should be able to see 192.0.0.64 respond to a ping as the camera boots up. Can you set a continuous ping on the Mac to check?
If you get a response from 192.0.0.64 for a few seconds and then nothing, and it does not return, your camera is likely to be configured to a fixed address that you really do need something like SADP or ONVIF Device Manager (Windows tool from sourceforge.net) to find.
Do you have a friend with a PC on a home network?
*edit* If you are connecting your camera to your home network, and it's a common address range, and have an Android phone, you might find the camera address with a scanner such as Fing.
*edit1* Just a thought - check out any response on 192.168.1.64 I have a vague recollection of a change log that suggested the default IP address was going to change away from 192.0.0.64 on some future version of firmware, but I can't be sure. I've not read any posts here to that effect.