Un-integrate Parallels for Mac OS X When installing Parallels in Mac OS X 10.6 I believe I chose to integrate Windows XP with OS X. Some files are now associated with programs in Windows even though there are OS X equivalents. This is annoying because it is easy to accidentally open Parallels and Windows. Very annoying. 

So my question is: can I un-integrate Parallels?
Power off your VM, open Parallels Desktop, select the VM you wish to modify then in the menu bar select Virtual Machine -> Configure...

You'll get a Options window where you can change all the settings of the VM.  Specifically to your application problem, you can modify those settings underneath Options -> Applications.  I'd uncheck "Share Windows applications with Mac".

After completing that step you'll need to manually rebuild the LaunchServices database.  Open Terminal and run the following (without the $):

 $ /System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Support/lsregister -kill -r -domain local -domain system -domain user
 $ killall Finder