Transfering games without installing.

[Fledge]

I've got a few of games on my e-hdd from when I last did a backup using it. Now I've done a clean install (of windows) I'll need to install my games again. However, I can't just transfer the files to my hdd from my e-hdd because there would be no installation process and thus not a proper install so the game should not work.
I still tried it. I copied everything from Starcraft II onto my hdd and it seems to work fine (for the 10mins I tried) - which is surprising and a little confusing because everyone I've consulted on the subject has said NO YOU MUST INSTALL OR IT BREAKS EVERYTHING.
The game does not appear in the windows game folder so I have to launch directly using the .exe.
I will install it properly (once I get the disk back from a friend who's using it for a trial install) but I was wondering what you could make of this. Is it safe to play this uninstalled game?

 

[hood1971]

Completely depends on if the game installs reg keys, has saves in places other than install folder etc, which most do. You can try running each game to see if it works, but if you have the discs just run the install.

 

[tibbsey]

Blizzard games seem to be ok with this, several people I know run WoW straight off external hdds that have just had the files dumped on them.

Ultimately I believe it depends on the game and how it works.

 

[HummuH1]

I did this about 6 months ago. I copied the main installation folders and any user data across.

Some games worked fine (Starcraft II included) but I'd say the majority didn't and I ended up doing full re-installs just to be safe.