I know this has been covered on other sites but I thought I would post it here for the benefit of our readers.  Why would you want to do this?  Well, because Notepad that comes with Windows is, well, if you’ve used it then you know what it’s like and have probably moved on to something better. However, simply adding an additional text editor doesn’t change the fact that Notepad will still open as the default editor for many files within Windows Vista.  So how do you accomplish this?  It’s (almost) simple:

• Open a command-prompt with administrator priveleges (right-click, run as administrator).  If you have UAC disabled then you can open a regular command-prompt.
• Take ownership of notepad.exe using takeown /f c:\windows\system32\notepad.exe
• Grant yourself full access rights using cacls c:\windows\system32\notepad.exe /G <username>:F (replacing <username> with your username)
• Using Explorer, replace notepad.exe with the editor you would like to use after renaming it to notepad.exe
  • If you are using Notepad2 to replace Notepad you would just rename Notepad2.exe to Notepad.exe