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?
Best Answer
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 $):