http://windows7tips.com/environment-variables-windows-vista-7.html

Variable Typical value (may vary)
%ALLUSERSPROFILE% C:\ProgramData
%APPDATA% C:\Users\(username}\AppData\Roaming
%CommonProgramFiles% C:\Program Files\Common Files
%COMPUTERNAME% {computername}
%COMSPEC% C:\Windows\System32\cmd.exe
%HOMEDRIVE% C: or sometimes D:
%HOMEPATH% \Users\{username}
%LOCALAPPDATA% C:\Users\{username}\AppData\Local
%PATH% Varies. Includes
C:\Windows\System32\;C:\Windows\
%PATHEXT% .COM; .EXE; .BAT; .CMD; .VBS; .VBE;
.JS ; .WSF; .WSH; .MSC
%ProgramData% C:\ProgramData
%PROGRAMFILES% Directory containing program files, usually C:\Program Files
%ProgramFiles(x86)% In 64-bit systems, directory containing
32-bit programs. Usually C:\Program
Files (x86)
%PROMPT% Code for current command prompt
format. Code is usually $P$G
%Public% C:\Users\Public
%SYSTEMDRIVE% The drive containing the Windows root
directory, usually C:
%SYSTEMROOT% The Windows root directory, usually
C:\Windows
%TEMP% and %TMP% C:\Users\{Username}
\AppData\Local\Temp
%USERNAME% {username}
%USERPROFILE% C:\Users\{username}
%WINDIR% Usually C:\Windows
Note the changes from Windows XP for the locations of many of the personal files and settings. For example, the « Documents and Settings » folder is gone and there is now a « Users » folder. There are also four new environment variables listed in Table I. These are:

%CommonProgramFiles%
%LocalAppdata%
%ProgramData%
%Public%
The common dynamic variables are similar to those given for XP.

Changes in environment variables between Vista and Windows 7 or 8

There are few changes in the common variables in going from Windows Vista to Windows 7 or Windows 8. As far as I can tell, there is only one worth mentioning. Windows 7 and 8 come with the newer Microsoft command line shell called Powershell. There is an environment variable %PSModulePath% that gives the path to the files for the command line shell. This is usually C:\windows\system32\WindowsPowerShell\v1.0\Modules\

List environment variables in Windows 7 or 8 using PowerShell

In the classical command line, environment variables can be listed with the « set » command. Beginning with Windows7, Microsoft began including the newer command shell called « PowerShell ». The command for listing environment variables in this newer shell is Get-ChildItem Env: