'ipconfig' is not recognized as an internal or external command, Windows 7

Sometimes uninstalling programs (worst case, viruses) could result in PATH in Windows environmental variables to loose track of some of main cores of the Windows system. E.g. if you run ipconfig in the CMD and gets this error: "'ipconfig' is not recognized as an internal or external command,
operable program or batch file.", then you might want to have a look at the PATH variable and see if  
C:\Windows;C:\Windows\system32
are missing ...

• Right click on computer
• Choose Properties
• Choose Advanced Settings from left bar
• Environmental Variables
• PATH