Notepad++

Notepad++ is a free (as in "free speech" and also as in "free beer") source code editor and Notepad replacement that supports several languages. Running in the MS Windows environment, its use is governed by GPL License.
Based on the powerful editing component Scintilla, Notepad++ is written in C++ and uses pure Win32 API and STL which ensures a higher execution speed and smaller program size. By optimizing as many routines as possible without losing user friendliness, Notepad++ is trying to reduce the world carbon dioxide emissions. When using less CPU power, the PC can throttle down and reduce power consumption, resulting in a greener environment.

Features

• Syntax Highlighting and Syntax Folding
• User Defined Syntax Highlighting and Folding: screenshot 1, screenshot 2, screenshot 3 and screenshot 4
• PCRE (Perl Compatible Regular Expression) Search/Replace
• GUI entirely customizable: minimalist, tab with close button, multi-line tab, vertical tab and vertical document list
• Document Map
• Auto-completion: Word completion, Function completion and  Function parameters hint
• Multi-Document (Tab interface)
• Multi-View
• WYSIWYG (Printing)
• Zoom in and zoom out
• Multi-Language environment supported
• Bookmark
• Macro recording and playback
• Launch with different arguments

If you have any problem to launch Notepad++ online demo, you can get support here.

• Notepad++ Installer : Take this one if you have no idea which one you should take.
• Notepad++ zip package : Don't want to use installer? Check this one (zip format).
• Notepad++ 7z package : Don't want to use installer? 7z format.
• Notepad++ minimalist package : No theme, no plugin, no updater, quick download and play directly. 7z format.
• SHA-1 digests for binary packages : Check it if you're paranoid.
• Notepad++ source code : The source code of current version.

You can find sha1 digests for binaries package on Sourceforge as well.

Notepad++ v6.5.3 new features and bug fixes:

1. Make advanced scrolling optional so it can be disabled in case of touchpad scrolling problem.
2. Enhance sort lines feature: if several lines are selected, only the selected lines are sorted.
3. Add hex value column in Ascii Insert Panel.
4. Enhance performance: prevent switched-in document from being parsed by function list and by document map while these 2 panels are hidden.
5. Fix the bug that modified tab interface colour settings cannot be saved in stylers configurator.
6. Fix text crazy flickering while resizing the frame on a specific position.
7. Fix the context menu not shown for the all other users (accounts) in the same PC.

If you face any problem while understanding any part feel free to share your comment. I feel glad to help you