ROMs and Emulators.

Just a question.

It is legal to own a ROM for 24 hours (then must be deleted) to try before you buy.

Also, It is legal to own a ROM if you own the original cartridge.

So, Heres the question:
If you don’t own the actual game console, Can you buy a cartridge, download the ROM, Play the ROM, and when you've finished it, return the Cartridge in mint condition?

Here's the scoop direct from Nintendo. Their answer is no. I'm sure other vendors feel the same.

whether you have an authentic game or not, or whether you have possession of a Nintendo ROM for a limited amount of time, i.e. 24 hours, it is illegal to download and play a Nintendo ROM from the Internet.

I don't know if you've heard the news, but Nintendo is planning on selling their older games as downloads which can be used on their new console platform. Read about this feature here.

well no one is never gonna sue you for using a 15 yr old game so download away. just dont host em online.