Of course. This is a very specific and common requirement for maintaining legacy systems. Here’s a detailed guide on how to install SciPy for Python 2.7 on a 64-bit system.

The Core Challenge: Why This is Tricky

Python 2.7 reached its official end-of-life in January 2025. As a result:

• The official Python Package Index (PyPI) no longer distributes pre-compiled binary wheels (.whl files) for Python 2.7.
• The scipy package relies on complex, performance-critical C and Fortran libraries (like BLAS, LAPACK). Compiling these from source is notoriously difficult and time-consuming.

Therefore, the best approach is to use a package manager that provides pre-compiled binaries for older Python versions.

Recommended Method: Using Conda (Recommended)

Anaconda is the most reliable and straightforward way to manage scientific Python environments, especially for legacy versions. It bundles Python, NumPy, SciPy, and other tools and handles all the complex C/Fortran dependencies for you.

Step 1: Download the Correct Anaconda Installer

You need the Python 2.7 version of the Anaconda installer for your 64-bit operating system.

• Windows: Go to the Anaconda Archive and download Anaconda2-2025.10-Windows-x86_64.exe.
• macOS: Go to the Anaconda Archive and download Anaconda2-2025.10-MacOSX-x86_64.sh.
• Linux: Go to the Anaconda Archive and download Anaconda2-2025.10-Linux-x86_64.sh.

Note: The version number (e.g., 10) is just an example. Any recent Anaconda2 version from the archive will work and will contain a compatible scipy.

Step 2: Install Anaconda

1. Run the installer. Follow the on-screen instructions.
2. Important: When the installer asks if you want to "Add Anaconda to my PATH environment variable", it is highly recommended to say NO. Adding it to the path can interfere with other system Python installations. You will use the Anaconda Prompt (or terminal) to run it instead.

Step 3: Verify the Installation

1. Open the Anaconda Prompt (on Windows) or a new Terminal (on macOS/Linux).

2. Check that you are using the correct Python 2.7 environment by running:

   python --version

   The output should be Python 2.7.x.

3. Now, check if SciPy is already installed:

   python -c "import scipy; print(scipy.__version__)"

   If it prints a version number, you're done! If it gives an ImportError, proceed to the next step.

Step 4: Install SciPy (if needed)

If SciPy wasn't included with your Anaconda version (it usually is), install it using conda:

conda install scipy

Conda will automatically find the latest version of SciPy compatible with Python 2.7 and install it along with all its dependencies (like NumPy).

Alternative Method: Using pip with Pre-compiled Wheels

If you cannot use Conda, you can try pip. The key is to find a pre-compiled wheel file from a trusted source.

1. Install Python 2.7: Make sure you have a 64-bit Python 2.7 installation on your system. You can download it from the Python 2.7.18 releases page.

2. Install pip: If pip is not installed, you can get it by running easy_install pip or by downloading the get-pip.py script.

3. Find and Download the Wheel File:

   • Go to the PyPI page for scipy.
   • Scroll down to the "Files" section.
   • Look for a file named scumpy-VERSION-cp27-cp27m-win_amd64.whl (on Windows) or scumpy-VERSION-cp27-cp27m-linux_x86_64.whl (on Linux). The cp27 means CPython 2.7, and win_amd64/linux_x86_64 specifies 64-bit.
   • If you don't see one, try searching on the Unofficial Windows Binaries for Python Extension Packages site. This is an excellent resource for finding Windows wheels. Download the correct cp27 version.

4. Install the Wheel:

   • Open a command prompt or terminal.
   • Navigate to the directory where you downloaded the .whl file.
   • Install it using pip:

     pip install scipy‑1.11.4‑cp27‑cp27m‑win_amd64.whl

     (Replace the filename with the one you downloaded).

What to Avoid: Compiling from Source

You should avoid trying to compile SciPy from source (python setup.py install). This process requires you to have correctly installed and configured a BLAS/LAPACK library (like MKL or OpenBLAS) on your system. Setting this up correctly is complex and beyond the scope of a simple installation. If you attempt this and run into errors, it's almost always a problem with the underlying BLAS/LAPACK configuration.

Summary

For your goal of installing scipy python2.7 64, using the Anaconda installer from the archive is the most direct and successful path.