If it doesnt work, try take the battery out of the motherboard and insert it again to restore it, that way it might recognize it. (This is what I had to to with mine)
To be honest, what I did in the old office at work when I was helping them upgrading it by making a desk, was getting seven EUR pallets and make my own desk by putting three long planks with the planks from the pallets on top. Just go over with steelbrush, fast over with a cutting torch to get...
I believe one of these might help, as nr 2 helped me when I changed my GPU a while back.
1. Do your PSU give enough power to power everything?
2. Try taking out the battery from the motherboard(this helped me by setting everything on the BIOS to default, but if you have custom settings there...