yeah, there is a USB HID extension being loaded, which is what I figured was needed to make a mouse work.

For OS 8.6 you needed drivers, not sure if 9.1 needed them or not.

Okay. I tried one card and it didn't work well, but I have a couple more I can try.

Should be, the USB card I got for my 8500 back in 2002 supported 8.6 or higher.

A recent dumpster diving trip rewarded me with a Power Computing 604/150, which is a 150 MHz PPC 604 mac clone. It's got three PCI slots, 384 MB of memory, and a 2 GB SCSI hard dr…