Yes, garry's mod will work with portal and you will have all the HL2 stuff.
No
Not specifically. You need a VALVE game to play Garry's Mod, one of which could be Half-Life 2.
If you are running on Windows Vista or higher, please run the program as an administrator. Also, make sure you are launching the game through Steam, nothing else will work! If none of these work, I highly recommend you uninstall, redownload, and reinstall the program through Steam instead of fiddling around with the settings and messing up your whole Steam Engine.
In general you only get props in Garry's Mod if they exist on your system, or in other words if you have that particular Source game installed. Whilst Portal might contain some generic Source props (and Garry's Mod may supply some itself) it's entirely likely that some (if not most) of the HL2 props will be missing if you don't have HL2
No, The Orange Box does not include Garry's Mod (instead it has HL2, HL2 EP 1 and 2, Portal and TF2). I wish it did have Garry's Mod.
Yes but its called "Orange Box" and included are HL2 episodes 1&2 and TF2 and Portal
Eh? how is it possible to have HL2 installed on you computer but not on steam? The short answer is no. But you're welcome to try clicking "add a game in the bottom left corner of your library and adding half life 2 as a game.
No, there is not any games like gary's mod, but there is JBmod....a different version of garys mod, find it here. (see related link) It requires HL2 (Half life 2) so if you want another game like it, you have to buy HL2.
Are you kidding me, Half life 2 is not even a multiplayer game. Ofcourse you can't, but there is a separate game called Half life 2 deathmatch. That is basicly hl2 multiplayer but i don't know if it is for PS3.
PC- sv_cheats 1 = Activate Cheats. noclip = Fly and go through walls. impulse 101 = Get all HL2 weapons and activates the HUD. god = You never get murdered
No, left 4 dead will only work for left 4 dead mods.
If you have HL2 on PC just go to your steam page and go to library and click on the tools bar and you should see a icon that says Source SDK. SDK is free and able to be downloaded if you own HL2, Ep.2, Ep.1, TF2 or portal. once you download it, you can make, play, and share you levels.