the reason it may not have worked (loaded)on your pc, is as you said you all ready had a version installed and a seriel number stored on you pc and it would have clashed with the one you accidently tried installing.
there should be no reason why it cannot be installed on your friends pc after uninstalling his dodgy version.
There might be if you could find out what drive it was supposed to come with,without knowing that i dont think you can do a lot. In your first post you said " OEM suite of nero in the box (proper disc) with the serial number and everything! very weird" with the serial number you can just install on any pc,even you mates and it should work he will need to uninstall the old copy first and use the nero clean tool to completly remove the bits left in the reg.