A more straightforward fix to python path issues (although somewhat drastic) is to entirely uninstall arcgis and python, make sure they are both all gone (including using Esri's uninstall uitlity AND the Control Panel add/remove programs wizard), then reinstall ArcGIS "clean" (this will set up Python too).
Often multiple versions of python and leftovers from incomplete uinstalls can totally mess up anything that uses Python. This can easily happen if you have other versions installed before you installed this version of ArcGIS.