I am currently running 10.4 Tiger on my mac and when I try to boot i get a picture of a globe and then a question mark and the finder icon blink in a folder. Then it acts as if it will start up and instead go to a blinking black screen that says: "dyld: Library not loaded" /usr/lib/libconv.2.dylib Referenced from: /bin/sh Reason: Incompatible library version: sh requires version 7.0.0 or later, but libi .2.dylib provides version 5.0.0" This probably was caused because I'm trying to upgrade it to Mac OS X Leopard 10.5 from and external hard drive. I cannot reinstall 10.4 Tiger because the DVD drive will not open. I cannot enter safe mode either. Mac will not boot with or without external drive. When I try to boot up in safe mode it shows text with a power button in the background and tells me to restart. When I hold Option on boot to select what to boot from and select the Internal Drive with tiger on it, it goes straight to the blinking black screen.