live cd issues

hello. i got 2 live cds with 5 distros on each. i decided to test the distros on my macbook but I couldn't boot from the Live CD using reboot and holding down "c", so I selected the Live CD as my startup disk. so i experimented with fedora, tested mint, and played with pradus. i hoped to shutdown and have mac osx back there but eiter i boot from the live cd or a mesage saying

Quote:

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Error is that no valid boot disk is available

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Run the boot script in my signature, and post the resulting file. It sounds like you messed up your boot loader.