Why is monitor's screen blank when I start up my computer?
Answer: First, check if the monitor plugged in to a power outlet and is connected to the computer securely. Some monitors won't function even if the connection is slightly loose. If the monitor is connected correctly, make sure that the power button is on. If the power light is not glowing, the outlet may not be providing power to the monitor or the monitor may have a dead power supply.
If the power light is on and nothing comes up on the screen when you start your computer, it is possible you have a bad video card. Test the monitor on another computer to see if the display works with another video card. If it does, try starting up your computer in safe mode by holding down the F8 key as the computer boots up. This should solve any screen resolution or color setting conflicts that may prevent your monitor from displaying an image.
If the monitor is still blank when you start up in safe mode, you should open your computer (after unplugging it) and check to make sure your video card is seeded properly in the motherboard. If the video card is properly connected and the display still does not work, you will probably have to replace the video card in your computer. While high-end video cards can cost $500 or more, you can get a decent video card for about $100. Check you computer's manual to see if your computer uses a PCI or AGP video card before buying a new one.
If the monitor didn't work even when you connected it up to another machine, the monitor has probably gone bad. Check the cable to make sure it is not broken or frayed anywhere. Then make sure the pins on the connector aren't broken or bent either, as even one bad pin can cause the video connection to fail. If you have a CRT monitor, do not attempt to open the monitor, as it may store an electric charge powerful enough to electrocute you. Even if you have a flat-screen display, do not attempt to repair it yourself, as it does not have any user-serviceable parts. Instead, take the monitor in to your local computer repair shop and have them repair or replace it for you.