How can i play old video games on my computer?

[Phineas]

I want to play old games like Contra, Contra Force, Super Mario and Virtual Cop on my computer. How is this possible? Please give me detailed help. I've heard that i can install a game boy emulator on my comp and download and play these games.

[Jesuszilla]

Emulation. I could give links to emulators, but there's info all around Google for that. Not to mention most sites I know also host ROMs, which are not to be posted here.