This is an answer simply because I can't fit it all in a comment, or several...
To install and run PyMOL, you'll need a few extras. They are all free and open-source:
Python 2.7.10: Make sure you choose to install
pip during the setup process, and also choose to add Python to your PATH, if that option is given. Also, note whether you installed the 32-bit version (x86 MSI installer) or the 64-bit one (x86_64). Which you choose depends on your operating system - if you have a 32-bit OS, you only have one choice. If you have 64-bit Windows, you can do either one - there's no real difference to the casual user. I like 64-bit, but I'm a nerd :)
numpy+mkl package: I'd get version 1.9.2, as 1.10.0b1 is a beta version. Make sure it's not one of the "unoptimized" builds! You want the
cp27 (stands for CPython 2.7) package, either 32- or 64-bit, matching your choice above.
From the same page, the
PMW package (choose the
PyMOL itself (both
pymol_launcher packages for cp27).
Once you have everything downloaded and Python installed, open the command prompt by hitting WinR, typing
cmd into the box, and hitting Enter. Use the
cd command to change to the directory where you downloaded the
.whl files (paths with spaces in them should be completely enclosed in double quotes:
cd "C:\Users\John Smith\Downloads"). Next, type
pip -V to ensure pip works. If it doesn't, just use the whole path:
C:\Python27\Scripts\pip -V. Once you get the version statement, you're good to go. For each filename, type
pip install really_long_filename.whl to install it. Remember that you can start typing a long name, then hit Tab to complete it. Do this for all four wheels -
pymol_launcher - in that order.
Once you do that, you should be all set. I'm not on Windows at the moment, so I can't tell you whether you'll get an icon or not, but if you don't, then open Windows Explorer and browse to the
C:\Python27\Scripts directory - there may be a PyMOL script there you can run.
If you have any questions, please ask on Stack Overflow, tagging the question with
[pymol]. People are generally very quick with comments and/or answers, so please stick around on the question's page for 5 or 10 minutes to assist those who would help you.