The most common fixes for the the ‘No Signal Input’ error on your screen are:

• POWER and Cabling Issues: This may seem self-evident, but the solution could be as simple as double-checking all electrical connections and ensuring the input device is turned on. Make sure your video monitor cable or HDMI cable is securely attached to the PC or other input device as well as the display. If you're using a desktop tower computer, ensure it's turned on. Some PCs feature cooling fans that spin and create noise even when the computer is not turned on. Check that the power light is on and that the monitor and computer are both connected to a power supply. If you ever discover that your monitor isn't turning on properly, this is a superb method to employ. Examine the state of your power cord. This display problem can be caused by a faulty power cord or power STRIP. When working with a frayed or damaged power cord, use caution.
• SOURCE of Input is Incorrect: Make sure the correct input source is selected if your monitor has multiple input channels. If you're using a video output or HDMI cable to connect to a PC, make sure the monitor input is set to the correct source, such as HDMI or Video. You can normally accomplish this by pushing the menu button until you find the input button on the monitor's MAIN menu or control panel, then selecting the input button to cycle through the settings until you obtain the correct video signal.
• Setting the Monitor Resolution: If the monitor display resolutions are out of sync with the input signal, some external display monitors will display no image and an error message. The monitor may display a "no input signal" message if your PC video card or graphics card is set to a display resolution higher than the monitor's native display resolution. To find out what your monitor's maximum and native resolutions are, look at its specifications. If you're not sure and have a Windows PC, consider starting it in safe mode, which has a lower display resolution.
• Problems with Graphics Cards: If you're using a graphics card that can be swapped out, check sure it's firmly seated in its slot. Before removing an internal graphics card, make sure all cables are disconnected and the device is turned off. A display device may produce an error message due to a faulty video card or an incompatible video card driver. When a computer is turned on, never remove the cover.
• Experiment using a different cable or a computer: A damaged video cable is also likely to be the source of the monitor's lack of signal. If the problem persists, try connecting your monitor and PC with a fresh cable. If not, the problem is due to a problem with your video cable. If the problem persists, try connecting your monitor to a different computer. If your monitor STILL displays the no signal message, it's possible that the monitor is the source of the problem. In this scenario, you should seek further advice from the monitor's manufacturer.