I am talking about when you power on your Mac and it stops at one of the boot up screens. This has happened to me once (blue screen) but I have also heard about it getting stuck on the grey screen as well. I searched this both on Google and these specific forums and the only information I found on it was a list of commands to "try" if it happens, but not actually the cause of it. Is there a single or multiple known causes of this and is there a definitive remedy to this, or do you just have to trial and error and hope for the best and have the OS disc ready to reinstall it? I don't think anything is wrong with my Mac at all, not in the least, I think my experience was just a little hiccup - is that likely? Thanks everyone.