I have a G4 MDD that I use fairly regularly. I have software on it that I can't update and works for me right now. The screen has been getting a bit wonky over the last few months until it just would flicker on start up (still showing Apple icon) and then - multi-color snow. I realized the video card had gone. I pulled the card from the machine and noticed that 2 - 3 capacitor tops looked swollen. I found a replacement unit (Apple ATI Radeon 9600 pro 128mb 630-6630) on ebay and received it yesterday. I installed the card this morning and when I tried to boot the computer, I got nothing; no light, no tone, nothing. I was stunned but since I'd replaced the PSU (power supply unit) once already, I thought it had gone out while the machine was off waiting for the replacement video card. I checked the power cord, checked the battery and reset the PMU. All did nothing to help. Then out of curiosity, I removed the "new to me" video card, and put the old one back in. The computer fired right up with the lighted button and the chime. I didn't have a monitor connected, but I'm pretty sure the card was still faulty, however it did turn on. Has anyone had a video card impact start-up like this? What is causing the problem? Is the video card defective?