can you recommend any (opensource or trusted) android apps to check who's using your wifi? or any cmd prompt code to search on the desktop?

a small doubt: can anyone hack your computer through WiFi? If so, How to prevent that (or) How to take measures after you think you been hacked?

Extensions: Ad Block Plus, Ad Guard, FastForward, Skip Redirect, Firefox Translations, Youtube NonStop, AdBlocker for YouTube, Cookie Autodelete, Search by Image.

Thank you!

and is there a open-source shazam?

Can you also suggest a good opensource/affordable encryption software for hard drives?

In case of renaming multiple file extensions to another, they suggested to type this command in cmd promt or powershell: ren *.(current extension name) *.(new extension name)

But what about to renaming multiple file extensions to nil or no file extension? How to replace this command *.(new extension name) ?

Suddenly a website popped up on chrome tried to close it & there was a pop-up closed it again; then my firefox browser was refreshed & a NEW "hibro.txt" file was created on the desktop. Opened the txt file and they were addressing me & talking about how good of a gamer I am...

SO can you please explain HOW WAS the .txt file created by the hacker & HOW THE HELL did they know I'm a player of xyz game?? COULD THEY HAVE ACCESS of my files, folders and family pictures too? PLEASE HELP and KINDLY CLARIFY MY DOUBTS!

thank you.

I use winrar.