Major startup problems


I recently attempted to install "Missing Sync" in OSX Panther. I was required to do a startup. When the computer shut down and started up again, I got the grey apple for a while and then the prohibit sign. Tried to boot in safe mode: same thing. Tried to boot from install disc: same thing. I was able to boot into OS9.2 on a different drive and from there tried to use the OS9 disk first aid tool on the OSX install disc to erase the startup drive, but this didn't work either. As soon as the computer restarted to install OSX, I had the same problem. Please HELP!!!!!