I have just bought a MAcBook and was trying to get my Time machine hard drive that's connected to iMac to act as a shared drive (it now appears I can't do that), and in doing so I came across the privileges option in the 'shared' options in 'system preferences'. So, I thought Eureeka!! That's what I need....... I need some privileges....and so select my iMacs hard drive and clicked away....bad move!! Now, my mac won't boot. I now get a flashing folder with a ? mark in the middle. So I thought...I know I'll put in the Snow leopard installation disk and boot from that...still no, it trys to install a fresh copy of snow leopard and guess what........I can't install it onto my iMacs hard drive....pants!!! So, now what do I do??? Everything's backed up to my External hard drive so I'm not overly worried about losing my photos and music...etc etc.. But, I now have the worlds most expensive paperweight...please Help!!!!! Update....it's added permissions to my hard drive used for time machine...now I'm quite scared!! I've connected it to my MacBook, and I can't even look at it, as I haven't got permission......How do I get read write access to my time machine hard drive without destroying a lifetimes worth of photos, videos, etc etc....???? Update 2.......I now have my computer up and running again....heaven knows how?? However, i have 2 hard drives connected to it....one that stores all of my media and the other that is used for my time machine...I don't have access to either. How do I get access to my hard drives again?? I need all of my media!!! Help!!