One thing that's always been lacking in Windows is a good interface for creating or editing your environment variables, especially when it comes to PATH:
Se what I mean?
Fortunately, there's a great free utility called Rapid Environment Editor that not only makes it easier to edit variables, it will also tell you where you have bad values. Check it out:
It highlighted my Path in red to tell me there was a problem and when I expand Path, it shows the problematic entries. Brilliant!
I can delete these and save my environment with a cleaner PATH variable.
Feel free to give REE a try - http://www.rapidee.com