I have a 400 Mhz Blue G3 iMac, built in CDROM, running Jaguar. This thing started flat-out hard crashing a few minutes into sessions. I have a feeling it may be overheating or soemthing due to the nature of this behavior. What it did the first time, I was on the internet, eveything is going fine, then I discover that nothing is happening and the cursor is not moving. I can't do anything with the power switch in the front, and when I hit the restart button on the side, instead of going "Binnng!" it goes "THBBBBBBBT" and does pretty much nothing. So I leave it off for a bit, then try turning it back on again. It works, but only for a few minutes, then it crashes hard again. Every time I let it sit, it will let me use it for a bit. This time around, I had it off for days, then I booted up and started installing a couple of security updates. It worked through two of those, but when it restarted the second time, it hard crashed again, as I thought it might. This sound familiar to anyone?