Look For the Simplest Things First...

I was just in my computer room about to turn on my retro-gaming computer to play some old school Homeworld.  I pushed the on button and the computer whirred to life, but nothing would show on the screen. I took the side panel off and checked the video card and it was working correctly, or at least, the fan was spinning and the card was firmly in its socket. Stumped, I sat there for a few moments. Guess what it was? The cable to the monitor from the video card had come unplugged.  I plugging that cable back in, screwed it secured tight, and we were back to business.  Big sigh of relief on my part.