G5 dual 1.8 desktop won't boot

I've been trying to figure out what's up with my G5 dual 1.8 desktop mac here. A couple of months ago my monitor started to resemble the Matrix with random streaming "data" patterns. I'm almost certain that the computing was o.k., but I only could navigate through the monitor noise periodically, mostly it was complete blockage. I replaced my graphics card and it booted up with the monitor clear, but in the meantime I purchased a new IMac so I put it away in it's original shipping container. A few weeks have passed and I pulled it back out of it's box, I planned to use it as an auxiliary office machine, but now I can't get it to boot up, no image on the monitor and no "chime". Any ideas what this can be? Oh yeah...I can start it up from the cd and ran the disk repair utility, the result was that "no repair necessary". What the heck!!??