The varieties of "doesn't read burned CD" are usually, doesn't read multisession, only DAO burned CDs, doesn't like the dye colors of particular blanks. Typically, gold or silver colored blanks work best in old drives, and highest success is meant to be from using CD-RW media burned disk at once. I haven't had edge cases that hate my CD-Rs enough to confirm that last though.
Bootable pressed CDs for that age of hardware are few and far between though. I think maybe Windows 98SE will boot you, but you'd have to know what you were doing to navigate out of the setup and use command line to do anything.
edit: forgot to mention the other issue, CD booting might not be supported at all. Always a possibility on stuff built before 2000.
Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.