Are you using the VM console or via SSH?
If you didn't go through the wizard at boot and answer the last question about root access via SSH, you will not be able to SSH into it at all.
What a drag. This was on the console. I don't recall seeing an option to go into a setup wizard after it booted. Luckily I just reinstalled it and it hasn't been running long, so I'll just redo it and try again.