Your G3 processor upgrade card is a Sonnet Crescendo L2 model, plugged into the L2 cache slot. Has the computer's internal 4.5-volt alkaline battery ever been replaced? One obvious symptom of a very weak/dead battery is the loss of the correct date/time, after the computer has been unplugged from electrical power and then reconnected and powered ON. Weak or dead batteries can cause startup problems, so it's usually the first recommended step in troubleshooting. Additionally, those alkaline batteries can leak, after having been fully-discharged for an extended time. The corrosion damage from leakage can ruin the motherboard. The battery is a small black plastic cube, having a red and black wire with a flat connector on the end, that's plugged into the motherboard. It's secured to the motherboard with velcro. To remove it, I use a non-conductive object, like a popsicle stick, to hold down the toothed plastic pad on the motherboard, while lifting up the battery (with the fuzzy pad on the bottom). A new battery will include another self-stick plastic toothed pad, in case the original pulls off the motherboard. The battery is a Rayovac 840, 841, or equivalent, and can be purchased from online merchants or from "battery specialty" retailers in your area.
