Installing a Steam game with the retail disc?

Hi peoples seen as though my brother has GTA IV on PC that he bought retail, and seen as though I just bought it off Steam for $7.50 am I able to install it from that disc?

Probably. You can try.

" Probably. You can try. "

This can work, however it's not supported and some games it will just not work with.
 

1. Install the game (somewhere)
2. Backup the installation folder to a separate location
3. Uninstall the game
4. Start the Steam download/installation of the game
5. Pause the download once it's started (some people like to let it get to 1-2%) 
6. Exit Steam once you've paused the download
7. Copy the backup over the folder in \Steam\steamapps\common\
8. Restart Steam
9. Go to My Games
10. Right-click on the game, click on Properties, then Local files
11. Click Verify integrity of game cache...
12. Let this finish, and unpause the download once it's done if verification didn't already

" This can work, however it's not supported and some games it will just not work with.  Install the game (somewhere) Backup the installation folder to a separate locationUninstall the game Start the Steam download/installation of the game Pause the download once it's started (some people like to let it get to 1-2%)  Exit Steam once you've paused the downloadCopy the backup over the folder in \Steam\steamapps\common\ Restart Steam Go to My Games Right-click on the game, click on Properties, then Local filesClick Verify integrity of game cache... Let this finish, and unpause the download once it's done if verification didn't already If this process doesn't work, you'll just need to straight up download the game. "