I bought my mom an iBook G4 on eBay a few months back. It's been working great until a few days ago. Her screen... I want to say it flickers but that's not right. It's like the display gets a little brighter for a second or two and then goes back to normal. I know this isn't good. I don't have any of the orignial software. Is there a way to run a hardware test still? I'm hoping it's not a huge problem (like the logicboard is failing). Any idea what it could be and how I could fix it? Thanks!