1. Click on Start\Run
2. Type notepad & hit enter
3. Paste these command
Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\*\shell\Open with Notepad]
[HKEY_CLASSES_ROOT\*\shell\Open with Notepad\command]
@="notepad.exe %1"
4. Save it as OpenWithNotepad.reg
5. Double click on it & click yes
* to remove these from right click content paste these command on notepad
Windows Registry Editor Version 5.00
[-HKEY_CLASSES_ROOT\*\shell\Open with Notepad]
Save it as RemoveOpenWithNotepad.reg
Double click on it & click yes.
Ps: If you are afraid of programming download this file containing two of these registry.