I replaced one of the fans, but didn't realize they were two different sizes. At any rate. I tried to reassemble so I could see if it was still working, but now it won't boot. I also have 4 small screws that don't fit into the outside case holes, so I must have mixed up some screws somewhere. Is there a way to tell what screws go in what holes? And what might I have forgotten to plug in to get this issue? Also, in step two, there is a small cover on the edge of the bottom. I took the cover off and there is a connecter in there. Does anyone know what that is for?