ok i want to show my friend half life 2 can i install it on his computer ? also can i put some save file on a CD then take them to his house and continue from where i left off?
If he's got Steam you should be able to log on using your account and download HL2. It'll only be playable when he's logged in using your account. All save files are kept in "Steam Install Path\SteamApps\[email protected]\half-life 2\hl2\SAVE"
It's easier if you have the bought CD or DVD version to do this, but you can also back-up the Steam files to CD or DVD if you downloaded the game via Steam and avoid downloading it all again. Either way, he needs internet access.
Just as long as both machines don't access your account at the same time, you should be okay.
I'd make sure you delete the program and Steam from his machine after you're finished just in case he does something in the future with pirated versions or CD codes that gets your account banned and you lose your copy of HL2.
