I have two errors going on. Input signal not found check the video cable and video source

[Sally102466]

Help!

My computer was working fine.  It got disconnected and when we tried connecting it back.  My nephew indicated he was going to perform a clean drive of all temporary files using a windows recovery tool.  The next thing he indicated was a windows 10 error code 80004001.  Im also getting a message: Input signal not found.  Check the video cable and video source.  I've checked the cables and they seem to be connected correctly. 

[WAWood]

@Sally102466 

Sorry to be blunt, but that error code means that your nephew trashed your OS -- plain and simple.  I don't know WHAT they were trying to do, but what you claimed they said makes no sense whatsoever.  So, either they told you something wrong, or they tried something proper but messed it up.  Either way, their messing with your PC trashed the OS.

We need to know if this is a laptop or desktop (folks post in the wrong section all the time) and what the model number is.

With a desktop, this means the video cable connecting the tower unit to the monitor has been disconnected or failed (last is very unlikely).  With a laptop, this means an internal fault that you will not be able to fix.