If you have no display, could be a power supply issue or a motherboard issue, maybe the video card if you have an add-one card. Check the motherboard for any capacitors that are puffy or have black stuff on top of them. That would mean bad motherboard. If you have onboard video and are using an card, remove the card and try the onboard video off the motherboard.
You can try to reset the BIOS by unplugging the computer from the wall and pulling out the CMOS battery on the motherboard for about 15 seconds, then try again. May as well reseat the RAM while you have the case open, and make sure fans and vents are all clean.
Did you actually check the cables to the monitor or just read about it?