If your computer turns on without issue, but your computer screen is showing a No Signal message, it could be due to problems in the CMOS, RAM, VGA card, or the cable that connects your CPU to your monitor.
This article will explain how to go about reestablishing a connection between your CPU and your accompanying monitor.
CPU Starts but Monitor Displays No Signal
All components inside the computer casing are prone to dust particles, which may deposit on the hardware components and prevent them from working properly. Before beginning, perform an initial check of your computer's main components for excessive dust build-up.
Once you've done an initial check of your computer, try cleaning your CMOS battery. The battery can be found attached to your motherboard, and can be cleaned by lightly rubbing the component. Next, take out your RAM and do a similar cleaning.
If you are still experiencing problems with your monitor's connection, check out your monitor cable and VGA. Clean both components individually.
Once done, reassemble your CPU. Your PC and monitor connection should be reestablished.