If you downloaded the game, no. If you purchased the game and it came with a disc, maybe. I wouldn't think that the disc is required to play, as the game associates itself with your steam account for verification.
This is possible, but only if the game already is available to buy from the Steam store. For example, if you have Half Life 1 from back when it was not on Steam, you can validate the CD key on Steam...and then play it without the disc through that. Games that Steam doesn't support however can not be translated over to Steam. Quite a few games are on Steam though, including EA recently adding a number of their games to it.
No.
If you bought the game from steam, no. and if your trying to put a game on your computer and it keeps adding to steam, than un-install steam while your trying to install the game.
No you have to keep putting the disc you can only play a saved game unless you have the game downloaded
You put the game in the disc drive it loads and u play the game
Slip the disc into the game slot
Yes, but it has to be on a disc.
put the disc in into the disc drive, and follow the steps, it will install, you dont need a manual to install a game
Buy platinum hits for 360 and put the disc thats not the game disc and it will downlod to your game disc.PS3 ,i think on the store
it depends if it is a game that is on steam (legit) it will go in there automatically if it is another game (for example, minecraft) then in the library, find add a game and pick "add a non steam game". if its not in the list then click browse and find it yourself.
No you can not put a PS2 game disc in the computer and play it The emulator programs will not work well and they require that you create a file and not play a game disc