I just did this... I ended up reformatting the drive and reinstalling, then restoring my time machine back up. U can try and fix it with refit rEFIt search google. your partitions are probably fine.. u just messed up your bootloader ,mbr, whatever its called. Thats why nothings working, it boots before everything else and thats why you cant do much. I was still able to load from my SL DVD and reformat. Be paitient and good luck