Just to share an experience from the last days:
Last year I bought a Sonnet Presto PCI-Card to upgrade one of the PCI Macs to Gigabit.
Choosing a product from Sonnet, without prior verification, I suspected, that I will find drivers for MacOS9 more likely, than when I blindly chose any gigabit...
My Sawtooth G4 400MHz AGP won't bootup anymore.
Only yesterday, I started the machine and it started as before. Today, in (likely) same setup, it does not startup anymore.
The power supply fan starts spinning. But no chime, no video.
Meanwhile I removed the SCSI card, the SATA card, the...