Goto the Start Menu
Right Click "Computer"
Select "Properties"
A dialog should pop up with a link on the left called "Advanced system settings". Click it.
In the System Properties dialog, click the button called "Environment Variables".
In the Environment Variables dialog look for "Path" under the System Variables window.
Add ";C:\Python27" to the end of it. The semicolon is the path separator on windows.
Click Ok and close the dialogs.
Now open up a new command prompt and type "python"
