I have a Dell Dimension 4700 and I did the system retore with ctrl plus F11. I can start the cpu in safe mode with networking and sometimes the cpu will start up normally but then sometimes it doesnt. It will go through th normal process and show the windows xp sign and then it doesnt go the main window where everything starts up. it just stays there and its black. I can move the mouse but nothing windows doesnt load. What can I do?