How to fix a modem?

My personal home computer is a rather old one but I like it and I am sure it has not gone completely wrong all the way. I have a big screen connected to the CPU which has been flickering since the past few days. Lately when I start the computer, the screen starts as usual with a flashing sound but nothing is being displayed on it. I waited for some time but still nothing. I performed a restart on the Central Processing Unit and the same scenario occurs.

I guess my computer screen has gone down but I am not so sure about it. Also the whole lot was bought together, so how can one part be damaged and the others still running. There must be more than one damaged part in the system. I do want to repair my PC based on your guidelines folks. Please advice.

How Android technology is used in modern phone or mobile devices and what is the importance in modern day to day living?