I’m not sure if this is the place for this question but hopefully someone can help. I have this Mac performa 6400 version 7.5.3 and I wanted to install a cable modem so I first installed an ethernet card. Then it turned out the cable modem was only compatible with versions 8.0 and higher on the mac. So I took out the ethernet card so I can return it. Now when I try to turn on the system I get no power. I checked to make sure nothing was loose, but I’m not sure what else to do. Please help.
