Thanks for your reply.
The fact that your machine will not boot from a CD, won't even power on, proves that this is a hardware issue. Which is what I suspected from your description of the symptoms.
When this happened to me the problem turned out to be a failed CPU cooling fan, and the overheating resulted in exactly the sort of screen anomalies you describe.
It was a bit easier to diagnose because that was an old K6 system with an AT power supply. Pushing the power button actually delivered full power to the motherboard. Once I opened up the box I could just throw the switch and see that the little fan was not spinning.
With a modern ATX system the power button is wired to the motherboard, which is always partially powered (very low current) as long as the cord is attached and the switch is set to "On." When you push the button, the motherboard responds by sending a signal to the power supply to turn itself on fully and start delivering voltage to the drives, fans and the rest of the motherboard. That starts the POST (power on self test) process that I'm sure you're familiar with -- the enumeration of memory, devices and drives, which precedes the search for a boot record on one of the drives.
What this means is that a no-power problem might _not_ be the power supply, it could be the motherboard. Another complicating factor is that power supply failures sometimes damage the motherboard and/or CPU, so all three components need to be checked out.
You need to post your problem in the Bleeping Computer Hardware forum. There are professional computer techs who give advice there, they can suggest specific troubleshooting procedures for you to follow.
To help them, please give as much specific information as you can about your computer system. Power supply make and model, motherboard make and model, processor, memory, drives, and so on.
Edit: after you get your hardware sorted you will need to reformat and reinstall Windows on your hard drive. Any software installed when the system is misbehaving is almost certain to have been copied incorrectly to disk, and the corrupted data will cause all manner of problems.
Best of luck in getting your system working. As the Irish say, I'm sorry for your trouble.
Edited by DaveM59, 03 February 2007 - 05:44 PM.