# Blinking cursor : that means something's wrong with your bootloader. 1st ensure that your OSX volume partition is set as active. Once it's ok, what you have to do is to rewrite the boot loader. To procede, 1st determine the BSD name of that drive (you can use the disk utility on the install DVD, right click your Volume (not the drive), you'll see something like DiskXsY. X is the drive, Y is the volume. This operation requires several files and utilities, it's recommended that you find the EFI package that contains all what you need. Put it on a thumb drive formated in HFS, plug it, launch your install DVD and launch the terminal from the installer. Then type the following (we consider you got that EFI package extracted directly on the root of your thumb drive, you can put it in an other folder but you'll have to replace the path to your thumbdrive with the one to your folder) :

    cd ./Volumes/THUMBDRIVE_name

    ./startupfiletool /dev/rdiskXsY ./Volumes/THUMBDRIVE_name/boot_v8
    dd if=./guid/boot1h of=/dev/rdiskXsY bs=512 count=1
    dd if=./guid/boot0 of=/dev/diskX bs=400 count=1

Notes : Replace the things in bold green with what you need. This guides tells you to procede from the installation DVD and a thumbdrive because we consider your OS isn't bootable since it's screwed. However you might have an other working OS to do it from or simply want to put your freshly downloaded EFI loader. The steps are the same.