I just installed 4GB memory into my 2.1 ghz white macbook. The memory is from crucial and it is for macs... I've pushed harder than should be necessary to try and set the memory in the slot. Its in there. When I turn my macbook on it goes to my log on screen. From there my keyboard and track pad do not work. It wont let me do anything. I can't type my password or move the cursor...? I'm completely lost! Any help would be appreciated!