I've acquired a Gateway, Model Profile 3, p/n 3501139, s/n-0026424357, from our old computers at work. I thought my friend's 5-yr old could use it. I have a mouse, keyboard and power adaptor, ADP-80AB Rev.B. When I plug it in, I can hear that it's powered up, but nothing comes on the screen. There's a place for some type of plug on the back that is marked l0l0l. Is this another cord that I need for it to work?