gigabyte motherboard ga-7n400 pro2 problem

[reor]

I replaced some ribbon cables in my pc and must of messed something up. So I switched them back but apparently my pci slots aren't being recognized. I can't load windows xp as a page comes up saying can not continue to protect the system. I can get win 98 and mellinium loaded but still have no pci slots recognized. I'd appreciate any help. Thanks.