G4 video trouble - any ideas?

I have a G4, about 8 years old. I moved the mouse to bring it out of the screen saver and the display was too dark and aqua colored (missing red or something). I reset, and this time, instead of seeing a slate-gray screen with the apple logo, there was a uniform aqua screen and no logo. Then the monitor went black and said "no signal input" (at normal brightness). The system must have booted, because I heard the apple chord, and when the caps lock is pressed on the keyboard, you can get the light to come on.

I took the monitor to a friend's house and plugged it in to another computer, and it had no problems at all. So it's not the monitor (V7 flat screen), or the cable. Is this a video card issue?

thanks...

yeah, sounds like a video card issue. try a apple hardware test. would be on one of the original discs that came with your computer.

Make sure the graphics display card is firmly seated in the AGP/PCI slot, whatever it is. If you have moved the computer sometimes they can work a little loose, but agree with above sounds like a dead card.

Update: I shut down and waited a couple of days. Then I opened the thing up, for the first time ever. There was a ton of dust. A ton. I cleaned some of it out and now it's all functional. Can dust actually affect the system like that?

8 years of dust? Wow. I'd clean more than just the card with some canned air.

Dust will affect all computers. Particularly so with the Mirror Disk Door series with their multi fan set up.