Okay, this problem just started happening today. Here's what I'm running: 1.5ghz G4 15"PB, OS10.3.9, and I've recently installed the latest security update, QT7, and Adium 0.8, if that's relevent in any way. Today while I was doing the normal surf/chat thing, with the usual applications open, the computer slowed down and froze for a few minutes, so I restarted. However, it would boot up (it just stayed on the grey apple screen with the little gear thing under it). I eventually got it to boot by using Command+Option+P+R after I turned the computer on, but it would run reaaaaallly slow, so after a few times doing this, I called Apple. After 45 minutes, and running some tests from the Software Install and Restore disc, we got nowhere. And then my cell phone dropped the call. So I figured I didn't feel like being on hold for another twenty minutes, so I didn't call back. Right now, my computer is only somewhat usable because I'm only running Finder and Safari. If I start running more applications, it only get's worse, and usually ends up freezing up again. If anybody has any advice, I'd really appreciate it.