Hi. I need some help. I've never experienced this before and this is the most trouble a Mac has ever given me.. Can anyone help me? I'm unable to open System Preferences for some reason. I'm afraid to do anything with the CD's that came with the iMac because I'm afraid that I'll lose my current OS (Snow Leopard). I can't open it on both accounts that I have on my iMac. Any help is much appreciated.