Hi, I have been having this problem when trying to install mountain lion. When I try to install mountain lion off of my flash drive I get stuck at a white screen with the mouse. I have done a little bit of searching around and found out that this problem most likely has something do to with my graphics card (AMD 6850) but I haven't found any solution to the problem. If someone could tell me what to do or give any advise that would be great! Thanks!