My Monitor has lost it's identity - How can I tell?

Question

*How can I get my computer to recognize my Apple monitor? The monitor does not seem to be telling the computer.*
Today my monitor started to jitter. I restarted the computer and watched the monitor view jitter and then collapse. It soon became a jittery mess.
I removed the monitor and attempted to install a PC monitor that I had available. It plugged in but would not light up. I unplugged it and plugged my Apple Display Monitor back in.
Now it worked, but the width of the active screen is very narrow. I went to the system preferences and attempted to fix the display, but when I did the jitter returned, making my monitor unreadable.
I replugged in the non-working PC monitor and then replugged in my apple monitor to get a view. I have the view but it is a PC narrow view. The computer does not seem to recognize the apple monitor.
How can I get my computer to recognize the Apple monitor? The monitor does not seem to be telling the computer.
- Thanks in advance for your help.

Answer 1

I found the Apple utility disk utility and used it. I am using an external LaCie disc burner. I clicked the Restore tab and navigated to the software & CD burner. The Restore button was greyed out so I hit the Burn icon instead. It worked.
I restarted with the disc and pressed "C". The disc mounted - success - but it said "this program does not work with this computer." hmmm.
Here's what I downloaded – it looked right?
693-3994-A.dmg
Apple Hardware Test (Power Mac G4) - Size 11 MB
AHT for Power Mac G4 Version 1.2.6, for use with Power Mac G4 (Gigabit Ethernet), Power Mac G4 (Digital Audio), Power Mac G4 (QuickSilver), and Power Mac G4 (QuickSilver 2002), added support for the NVIDIA GeForce2 Ti video card with (Gigabit Ethernet and Digital Audio) systems, Power Mac G4 (QuickSilver 2002ED), and PowerMac G4 (Mirrored Drive Doors).
Here is from my system profile:
Machine Name: Power Mac G4 (AGP graphics)
Machine Model: PowerMac3,1
CPU Type: PowerPC G4 (2.9)
Number Of CPUs: 1
CPU Speed: 500 MHz
L2 Cache (per CPU): 1 MB
Memory: 768 MB
Bus Speed: 100 MHz
Boot ROM Version: 4.2.8f1
Now which Hardware Software do I download. . .
The next Hardware Software in the list is:
Apple Hardware Test (Power Mac G4 Cube) - Size 18 MB
Apple Hardware Test for Power Mac G4 Cube version 1.1 CD for use with the Power Mac G4 Cube with CD-RW and the original Power Mac G4 Cube.
Download Now
This does not sound like my computer. I guess I have to try.
More stuff:
Today I tried a new experiment. I started with the 21" Display monitor connected but turned off. After start up I turned it on. The experiment failed. The monitor came on with the jitter.
I navigated blind to the System Preferences and the Monitor Display interface and hit something – some success – I accidentally lowered my resolution from 1280 x 1024 down to 1024 x 768. The jitter went away but I still have a narrow screen.
When I load the Apple Hardware Test Disk I am now able to do it without the Dead-Dell-monitor-switch.