You can't. If you have more than one xbox, obviously, you need more than one disc.
Saints Row 2 does not have local multiplayer. However, you can play multiplayer in the same house with a system link.
Saints Row 2 is a PS3 Xbox 360 game that is also available for the PC. You can read more about the game on the related link
Yes, you can play Microsoft Flight Simulator 2004 without a disc. I have put a link under this question explaining how to play Microsoft Flight Simulator 2004 without a disc. I have put a link instead of explaning how to do this because of the amount of steps.
The first disc game SYSTEM? There are I believe some add-ons from game systems (such as the Nintendo 64 DD) that allow them to play disc games, but I believe the first disc game system was the Phillips CD-i.
clean the disc or check your system
Unfortunately you cannot, if you look at the back of the case it says "Players: 1" but you can do a system link and play up to two players.
System link is a way to play with other people on the same network as yourself, so no you do not need live to system link but you do need to be on the same network
yes
System link is when you connect your and somebody else's console and play a match
No, both the disc's and the system's hardware and software are incompatible.
Unfortunately not. Even if you save the game to your hard drive, you still need the game in the system to play it. As soon as you take it out, the xbox goes back to the dashboard. The purpose for the "save to hard drive" option is to speed up in-game loading processes, that's all.
One can play Saints Row 2 on any of the gaming platforms for which it was released. These would be the Playstation 3 and Xbox 360, as well as the Microsoft Windows operating system for computers.