I was very happy to find a post how to easy install pymol 1.4 from source on windows.

1) Install python, 2.5, or 2.6 or 2.7 for windows.
2) Download appropriate installer from: http://www.lfd.uci.edu/~gohlke/pythonlibs/#pymol   Select according to your python version.
3) Run it
4) PyMOL is now installed in: C:\Python2X\PyMOL

A) C:\Python2X\PyMOL\PDB_file.reg   should be edited in a text editor, to match your python version. Run it.
B) Pymol is started by clicking C:\Python27\PyMOL\pymol.cmd   which executes python on C:\Python27\PyMOL\pymol-launch.py

Happy pymoling.