Win7 64-bit "Python is not an internal or external command" solution

The default Python is installed in the C:\Python27 directory

Some articles refer to the following solutions:

Method one, computer-> attribute-> Advanced system set-> environment variable-> system variable
Locate the path in the system variable, double-click Path, and add at the end; C:\Python27 "(do not quote, do not ignore semicolons)
Method two, run->cmd
Enter set path=%path%; C:\Python27
Next, in the current cmd under the input python, you can run

On the 64-bit Win7 platform, the second method, although it can

However, after the second way, the discovery closes the current CMD window, the open again will be invalidated, also need to reset by mode 2.