Notepad++ ist a very powerful free text editor, published under the GNU/GPL license and a very good replacement for Microsoft Notepad, especially if you code and/or want to avoide BOM (= Byte Order Marks) which can cause some problems. It is available for Windows operating systems.
If you write an article for our website, I strongly recommend Notepad++. This also avoides unneccessary code, which is useless for Joomla.