Of course. Here is a comprehensive guide for using Python 2.7.9 on Windows, covering its installation, key features, how to use it, and most importantly, the critical security implications.

⚠️ Critical Warning: Python 2.7 is End-of-Life (EOL)

Before you proceed, it is extremely important to understand the following:

• No Security Updates: Python 2.7 has not received official security updates since January 1, 2025. Any computer running Python 2.7 is vulnerable to known security exploits.
• No Bug Fixes: Critical bugs will not be fixed.
• Not Recommended for New Projects: You should only use Python 2.7 if you are maintaining a legacy application that cannot be upgraded.
• No Modern Libraries: Most new libraries and frameworks (like Django, NumPy, Pandas, etc.) have dropped support for Python 2. You will not be able to use them.

The only reason to install Python 2.7.9 today is for maintaining an old, legacy system. For any new development, you must use a modern version of Python (3.8+).

Key Features of Python 2.7.9

Python 2.7.9 was a significant release within the 2.x series because it was the first to include a major security feature:

• SSL/TLS Certificates (PEP 466): This was the most important addition. It bundled a newer version of OpenSSL and provided a ssl module that could properly verify TLS/SSL certificates. This was a direct response to the Heartbleed security vulnerability and made Python 2.7.9 much safer for web requests than earlier 2.7 versions. This is why it's a relatively "famous" or "stable" version in the legacy world.

How to Install Python 2.7.9 on Windows

The official Python website no longer hosts the old installers. You will need to find a reliable archive. A trusted source is the Python Archive on GitHub.

Step 1: Download the Installer

1. Go to the Python 2.7.9 Windows installer archive: https://www.python.org/downloads/release/python-279/

2. Scroll down to the "Files" section. You will see two options for Windows:

   • Windows x86-64 installer: For 64-bit versions of Windows.
   • Windows x86 installer: For 32-bit versions of Windows.

   To find out if your system is 32-bit or 64-bit:

   • Press the Windows Key + Pause/Break.
   • Look at "System type" under the "Device specifications" section.

3. Download the correct installer (e.g., python-2.7.9.msi).

   
   （图片来源网络，侵删）

Step 2: Run the Installer

1. Find the downloaded .msi file and double-click it to run the installer.

2. You will see the "Welcome to the Python 2.7.9 Setup Wizard". Click Next.

3. This is the most important step.

   • Ensure that the "Add python.exe to Path" option is checked. This is the easiest way to use Python from the Command Prompt.
   • It's recommended to keep the default installation path (C:\Python27).

4. Click Next and then Install.

5. The installer will run. When it's finished, uncheck the "View Readme" option and click Finish.

Step 3: Verify the Installation

1. Open a new Command Prompt (search for cmd in the Start Menu).

2. Type the following commands and press Enter after each one:

   python --version

   You should see:

   Python 2.7.9

   pip --version

   You should see the version of pip that came with Python 2.7.9 (it will likely be an older version).

If you get an error like 'python' is not recognized..., it means the "Add to Path" step was skipped. You will need to manually add C:\Python27 and C:\Python27\Scripts to your system's PATH environment variable.

How to Use Python 2.7.9

Once installed, you have a few main ways to interact with Python.

A. The Interactive Interpreter (REPL)

This is a command-line where you can type Python code and see the result immediately.

1. Open Command Prompt.

2. Type python and press Enter.

3. You'll see the Python prompt >>>.

4. You can now type Python 2 code.

   >>> print "Hello, World!"
   Hello, World!
   >>> 2 + 2
   4
   >>> a = "some text"
   >>> print a
   some text
   >>> exit()

B. Running Python Scripts (.py files)

This is how most applications work.

1. Open a simple text editor (like Notepad) or a code editor (like Notepad++, VS Code, or Sublime Text).

2. Write some Python 2 code. Note the print statement syntax.

   # my_legacy_script.py
   # This is a Python 2 script
   import sys
   print "Hello from a Python 2 script!"
   print "Python version:", sys.version
   print "The arguments passed to the script are:", sys.argv

3. Save the file with a .py extension (e.g., my_legacy_script.py).

4. Open Command Prompt, navigate to the directory where you saved the file, and run it:

   cd C:\Users\YourUser\Desktop
   python my_legacy_script.py

   Output:

   Hello from a Python 2 script!
   Python version: 2.7.9 (default, ...)
   The arguments passed to the script are: ['my_legacy_script.py']

C. Using pip to Manage Packages

pip is the package installer for Python. With Python 2.7.9, you have an older version of pip.

To upgrade pip itself (recommended):

python -m pip install --upgrade pip

To install a package: Let's say you need to install an old version of a library.

# Example: Install the 'requests' library
python -m pip install requests

⚠️ Security Warning with pip: The older pip and setuptools versions have their own security vulnerabilities. When you run pip install, you are trusting the package and the download process. For a legacy system, this risk is often accepted, but be aware of it.

Handling Python 2 vs. Python 3 on the Same Machine

If you need to have both Python 2.7 and a modern Python 3 on your computer, you can. The installer for Python 2.7.9 is smart enough to not take over the python command if you already have a Python 3 installation.

• The python command might point to Python 3.
• The Python 2.7 installer will create python.exe in its own folder (C:\Python27\python.exe).
• It will also create aliases like python2.exe and python2.7.exe in the C:\Python27\ and C:\Python27\Scripts\ directories.

To use your Python 2.7 installation specifically, you can call it directly:

C:\Python27\python.exe my_legacy_script.py

Or, if you added the Scripts folder to your PATH, you might be able to use:

python2.7 my_legacy_script.py

Summary