So. I've recently been having trouble booting my computer. I have snow leopard, updated to the newest version. Intel Core 2 Duo 2.2. 4Gb Patriot Ram. 180GB HDD. I replaced the hard drive, and the ram. I still encounter the problem. It will boot, but gets hung up on on the blue screen before the login screen appears (password). I went to the genius bar and they cannot find anything wrong with it from diagnostics. Is there something else that could be causing this??