There are many reasons to reinstall macOS. It can fix any one of several OS errors. Plus, it helps secure your Mac for sale if you need to wipe all of your data ...

It sounds like you might need to create an installation CD somehow. I don't know how you would do that on the PC.

-system -<BR>Powermac 5500/225<BR>OS 8.0<BR><BR>This will boot without extensions. Without bypassng them, the OS starts to load from either the CD or from the HDD but stops before any extensions ...