Is it legally possible to play Xbox, N-64, etc.... on your Pc without the game console connected to the pc? If so, how? And where would I be able to buy it?
It is free, they are called Emulators, they run on your PC. However, keep in mind that one Emulator can be 1+ gigs. Google them : ). Also, the Xbox ones, aren't very accurate, as in you should stick to playing them on an Xbox.
like above, yes it is possible. Legal on the other hand is a debatable issue. You are downloading roms of games and unless you own that system and game it is still considered illegal. I know that there are really no good PS2 emulators for PC, have not tried the Xbox versions, but older systems like Atari and NES usually work ok. I found them to be a real hassle as some games work fine, others have sound or control issues. you have an Xbox and want to play older games then go to a torrent site and search for Slayer 2.7 or there are rom & emulator discs called BAED. if your system if modded then you can use either one.