I have formatted my computer, earlier I was having the leopard and now I am thinking to install Lion and therefore, I purchased the OS X lion memory stick. When I tried to install that then that runs well for some time and then it shows me the message as problem under installing, please try again. It was not mentioned anything that can specify the problem. I tried to install that many of the times but that does not solved my problem. Can you tell me that what should I do to troubleshoot this issue or what is the reason for this problem.