So I wanted to show the file extensions in Windows Vista... It doesn't sound so difficult, right?
Well - it took me a while to figure it out since I thought that I'd better do it myself than look it up on the internet, so I will familiarize myself a bit with Vista, since the laptop I bought cannot be downgraded to XP (I really do not love Vista).
Anyway this is what you should do:
- Go to any folder you have on your desktop
- Click on the button Organise (this is usually found on the top left of the folder)

- Choose the View tab
- UNTICK 'Hide extensions for known file types'

Enjoy!
:-)