You Cant. Its impossible to get the "Real" Garrys mod 10, torrents are completely illegal and they never work. Just pay the $10 on steam.
gmod 9, yes gmod 10-no
gmod is 10$ at garrysmod.com
It costs about $10.
yes
Gmod 10 is a pay game. It can be purchased from the Steam store at http://store.steampowered.com It costs $10
if your talking about the gmod that you buy off steam, nothing game wise oh, and $10
I think you can use portal in gmod 10, but I'm not so sure.
gmod 10 is the last one, I don't think they'll release any more.
To download gmod for free, you must first find a website that offers the software for free. A simple search through the search engines should bring up quite a number of options for you to choose from.
go to steam.com here are some links related to Gmod to help you: Steam: http://store.steampowered.com/ Download stuff to Gmod here: http://www.garrysmod.org/downloads/ About Gmod: http://www.garrysmod.com/about/ Gmod fourums: http://www.facepunchstudios.com/
umm ok this doesnt make this much since, if your asking if gmod damages your computer, it depends on which gmod you have (if you got it free its gmod 9, if you got it for $10-13 its gmod 10/11). in gmod 9 there were LUA viruses, in gmod 10 there are fake addon viruses so you should just scan for viruses when you download addons (www.garrysmod.org). if you play online there are some players who find it enjoying to spam props and nukes until you crash. also if your computer is lower-end then some of the maps and addons can crash it. but OVERALL no, garrys mod does not damage your computer, some addons and players do. just be careful which addons you download. if your just playing gmod to build contraptions, probably no dammage there. OK now if your asking about some sort of computer in gmod (PCmod?) that damages players or something like that try www.facepunch.com/index.php
Garry's mod 9 is free, it was the last free version. it uses steam to launch as it resource files are all valve games. you cant star gmod without steam