My Computer and I: Fumbling in the Dark

My desktop is a 3-year-old Dell Dimension 8400. It was high-end at the time it was bought, but regardless is starting to show its age. I have upgraded some of its parts since then to keep playing World of Warcraft bearable, but of course it will need to be replaced eventually.

I have had my share of computer problems with my current computer (not suggesting that Dell is necessarily a poor computer assembler, mind you). Other than high school computing studies, I have had no formal training in maintaining a computer, so I usually need to end up experimenting when something goes wrong. Without further ado...

The Problem:
My LCD display suddenly stopped working. The screen went blank, even though the tower still seemed to be running.

Background Information:

• LCD displays are backlit with fluorescent tubes. Like the ones installed as room lighting, they, as well as any supporting components, are subject to a limited life (which is still much longer than that of incandescent globes).
• An LCD display is its own computer, even if a more simple embedded system. During the delay between one being turned on and an image appearing on the screen, it is booting up. Like a computer tower, a failure of any component will cause the entire display to stop working.
• If an LCD display manages to boot successfully but does not receive any video signal, it will display a default static image.

The Circumstances:

• The LCD display, just like the tower, was 5 years old when it stopped working.
• While power was being supplied to the display, it would respond only by blinking its power button green every 5 seconds. Unfortunately, my display's manual was on a CD, which I could not view on the computer because the display was not working!
• Not long before the problem, I had upgraded the video card from an nVidia GeForce 8400GS to a GeForce 210.

The Experience:

Some of the information the manual provides about the diagnostic lights at the back of the computer.

• I first suspected that the power to the display got cut. I tried unplugging and replugging the power cord to both the display and the power socket. That turned out to be futile, because the power button continued blinking green.
• I then checked the video card. Since the computer could not tell me what happened through the display, I needed to check the diagnostic lights. I was looking for a sequence of {Yellow,Green,Yellow,Green} for "A possible graphics card failure has occurred". I rebooted the computer (by pressing the power button twice) and checked the sequence. Once the lights stopped blinking, the tower signalled {Green,Green,Green,Green}; this eliminated not only a video card malfunction but also any other hardware failure in the tower.
• At this point, I suspected that the display failed. I bought an new display and connected it to the tower. It displayed computer images as per normal and I could see into the computer again!

Implications:

• My old display stopped working! Rest in peace.
• The display blinks its power button green when it fails to boot. However, I could not tell which component failed.