I have a 27" imac, with a 1tb hd installed when I received it, and I swapped out the optical drive for an SSD drive. The original HD has Lion on it, and the SSD has ML on it. I use the SSD as my OS, and just access itunes and iphoto from the original HD. I just received the imac from service, where they replaced the screen and graphics card. When I turned it on, I logged into the original HD, and I accidentally set the sharing and permissions on the SSD to custom, and now I cant start up via the SSD, and for some reason, my external HD, which are connected via fw, are also set to custom, and I cannot access them either. What can I do to fix this?