If you spend a lot of time in text editors, you almost certainly use something other than Windows' default Notepad. Weblog Online Tech Tips details how to set an alternative editor as your default to complete your Notepad replacement.
If you aren't already using a better alternative to Notepad, a gander at our Hive Five Best Text Editors is a good place to start looking for a replacement (we're particularly partial to Notepad++). Once you've got one, Online Tech Tips' step-by-step guide—which requires customising and running a batch file the author was kind enough to put together to ease the process—should do the trick.
The post uses a Notepad alternative called Notepad2, but from what we can tell the same replacement technique could work for any alternative you choose—you'll just need to read through the instructions and make sure you replace Notepad2 references with your text editor of choice. The post also focuses on Windows 7, but the same basic method should in theory work on any recent version of Windows. Just give the instructions a good read-through before you get started to make sure you've got everything set up correctly for your system.
Done this before, or got an easier solution for replacing Notepad as the default Windows text editor? Let's hear it in the comments.
Replace Notepad in Windows 7 [Online Tech Tips]