Editing your registry is not safe if you don't know what you're doing, you can easily end up screwing your computer.
You'd better use a tool like CrapCleaner/TuneUp Utilities and use the relevant function to enable/disable which app should be run or not.
CrapCleaner is freeware:
CCleaner is a freeware system optimization, privacy and cleaning tool. It removes unused files from your system - allowing Windows to run faster and freeing up valuable hard disk space. It also cleans traces of your online activities such as your Internet history. Additionally it contains a fully featured registry cleaner. But the best part is that it's fast (normally taking less than a second to run) and contains NO Spyware or Adware!