I don't know how many Pc's I've built and fixed over the years; I lost track. tonight I installed a new USB3 PCI slot adapter board. I removed the screw holding in the blank cover plate and pushed the board into the Motherboard slot, hooked up the 5 and 12 volt Molex power plug to it. Had a little trouble getting the mounting bracket to slide in, but got it in. Powered it back up, installed the new driver, and went to plug in a USB cable to try it out. DUH!!!!!!!!!!! I could not get it in. WHY? cause I never removed the blank cover plate. I did not notice it earlier because it does have holes punched into. Dark cramped work area, failing eyesight, and stupidity. No alcoholic drinks before doing it, but I think its Margarita time. fix it in the AM. OLE!