How to make Blender use Python2.x? When Blender is installed, it creates its own copy of Python 3.x. However, I prefer to code in Python 2.x. This makes it difficult for me to work with newer versions of Blender. I would like to know what to do so that Blender will instead use an external installation of Python 2.x, which I already have installed on my computer.

How do I make Blender recognize the other version of Python?
In summary - you can't. 

Since Blender 2.5 we've moved on to Python 3.x This means it is not possible to use Python 2.x for scripting in Blender.

Now it's impossible to build against Python 2.x, and even if you did manage by editing the source-code, you'd probably run into problems running Blender, since Blender's own scripts are coded in Python 3.

Setting PYTHONPATH to a non Python 3.3 installation like Python 2.7 will cause Blender to crash and die horribly. (So always make sure you don't have PYTHONPATH set to a non-compatible Python version. But you can use it to point to an external Python 3.3 installation that has extra modules installed that don't come bundled with Blender).

Note: with current Blender pointing to Python 3.1 or Python 3.2 will also fail. So make always sure you point your PYTHONPATH to same version as used in Blender, should you need the external one.

In the long run you'll be better off getting used to Python 3. Also here is the proposal for the switch.