Can you play n64 roms on your computer?

Not sure I understand your question, but I'll try to answer anyway. You press whatever key is assigned to the c buttons. I think that the default buttons are 2, 4, 6, and 8.

yes you can with a emulator but keep in mind its illegal

No

No, but there exist things called emulators that can be found on the internet that would allow you to play console games on a PC, however they arent always legal.

u play on because if you on the computer and looking up websites you play on it and if ur like throwing it up in the air and catching it that's playing with it