Hello NandhaKumar_90,
I'm John an Independent Advisor and a Microsoft user like you. I'll be happy to assist you today. I understand you have a problem with notepad not opening. Did you made any changes recently?
Let's try to reinstall Notepad if it helps.
Press Start then search Manage optional features
Find Notepad on the list then click Uninstall
Restart your PC
After that, Press Start then search then search Manage optional features
Click Add a feature
Select Notepad then Install
Please try to open Notepad
Kindly let me know if this helps or if you have any further concerns.
Sincerely
John DeV
Independent Advisor