This G3 just refuses to boot OS X. It's a 300Mhz "Mini tower". 384MB of ram, and an ATI Radeon 7000 32MB GPU. According to LEM I have a REV 2 logicboard. Mac OS 9.2.2 installs and boots just fine. What happens is when selecting the OS X install disc in Xpostfacto, it gives me this "can't OPEN" over and over again and eventually reboots. I am trying to install Tiger. Now, this also happens with Jaguar which is officially supported on this machine. It can boot the Jaguar install disc, but once installed booting to the internal HDD with Jaguar gives me the exact same output, forcing me to boot back into OS 9. I have been at this for about three days. The only thing on google I can find about this is to "Make sure the hard drive jumper is set to Master". Trust me, it is. So is the optical drive. I've tried different hard drives, removing the ZIP drive completely, I even put in a DVD drive to try a regular Tiger DVD. Same story. It just doesn't work. To answer all of the basic questions so none of you have to ask: Yes I am installing to a partition under 8GBs (7.4 to be exact). Partitioned with Drive Setup under OS 9. Yes I am positive it has a DVD drive, I installed it myself and tested it with a movie. Yes I checked all the jumpers on both the HDD and ODD. Both are Master on their respective controllers. Xpostfacto is configured properly - this shouldn't have anything to do with the Jaguar problem, though. My goal is a dualboot of Tiger, and OS 9. I was only installing Jag to see if it made a difference to upgrade to Tiger instead, that's when I found out Jaguar wouldn't work either. I appreciate all the help I can get with this, I'm stumped!