Recently, the older one turns on but does not do anything. I have tried connecting it to the monitor and keyboard, to see if the switch is the problem,but nothing got any better.
Ralph, when it comes to trying to help diagnose a computer problem like this it's difficult to pin point without more details.
You said it turns on but does not do anything. What, if anything, do you see on the screen once it turns on? Do you see anything at all on the screen during or after boot up?
I'm trying to determine if there's a problem with the graphics or video whether it's a stand alone card or that which is built into the motherboard. If this is a laptop, the video is built into the board.
I might also be a hard drive failure.
Again, we don't know what kind of computer - desktop or laptop. Anything else you can provide would help us help you.