... I'm smiling coz of the 68LC040 reference and the "may not work". The PB 190 runs 7.5.x to 8.1, so 8.0 should work just fine. The 68LC040 processor wasn't "strange", it just doesn't have that math coprocessor thingie. It should boot that disk just fine. But: You'll want a full installation package for that PowerBook, not just an emergency boot disk. Might find OS 8 installation disks on eBay. Or: Just go to an Apple dealer and kindly ask for the original system disks. Also: You'll find System 7.5.3 for free on the net somewhere and can update that for free to 7.5.5.
Mac user since 1987. Running Mac OS X 10.8 Mountain Lion on a MacBook Air 11" & an iMac 27" and whatever's newest for my iPhone 4s, iPad 3 and AppleTV 2.
Apple Certified System Administrator 10.6, Apple Sales Professional 2008-2011, Apple Certified Mac Technician.