There really isn't a way to install Steam to a custom directory, as it always wants to install in the default Program Files location -- usually C:\Program Files\ or C:\Program Files (x86). However, you can use the Windows "mklink" utility to create a file system pointer from the default location to wherever you want to store the files. Typically I do this with my game data files (everything under "\Steam\steamapps\common" within the Program Files folder), since these are the files that take up the most space.
Also, installing from a DVD is another matter, so I will answer that separately.
To install Steam data to a custom directory:
- Locate your game data, usually under C:\Program Files\Steam\steamapps\common or C:\Program Files (x86)\Steam\steamapps\common (if you have 64-bit system)
- Copy it to the new location
- Delete it from the original location (make sure you have it copied / backed up first!!)
- Open a command prompt by selecting Start and typing: cmd
- In the command prompt type the following (include the quotes): mklink /J "C:\Program Files\steam\steamapps\common\GAME" "c:[new location]\GAME"
- Example: mklink /J "C:\Program Files\steam\steamapps\common\altitude" "c:\games\altitude"
- This will create what is called an "NTFS symbolic link" (sort of like a directory shortcut) which transparently links Steam's default directory to whatever directory you specify.
There is also an app which will do the heavy lifting for you, called "Steam Mover".
To install a Steam game from a DVD instead of downloading it, do the following:
- Log in to Steam and click on Library.
- Right-click on the game, and select Delete local content.
- Insert the DVD and close Steam (Steam > Exit).
- Press Windows Key + R to open Run
- Type: "C:\Program Files\Steam\Steam.exe" -install D: (Replace "C:\Program Files\Steam\Steam.exe" with your actual Steam install location if different; replace D: with your DVD drive letter if different), and click OK.
- Steam will launch and ask you to sign in if you do not have your password saved. Your installation should continue from the disc.