The place where to change folder options has been changed since Windows Vista, which remains in Windows 7. It used to be located in tools –> folder options in windows explorer in Windows XP but since Vista, you can find them
either in Control Panel and Folder options
or Folder and Search options under Organize dropdown menu in Windows Explorer.
And then the following Folder and Search options window pops up, in where you can change some advanced settings to change the way how you browser your folders and files.
Wait a second, where is the File Types that used to be in the same window where I can manually set up the file associations? Here is how:
Right-click the file and choose properties. If the file type of the file you choose is not a executable file, you will see Change button under General tab where you can re-define the file association.