I swapped my motherboard and CPU too a month ago (from an SB i3 on an H61 mobo to an Ivy Bridge Pentium on a B75 mobo) and everything worked fine on the same in

I swapped my motherboard and CPU too a month ago (from an SB i3 on an H61 mobo to an Ivy Bridge Pentium on a B75 mobo) and everything worked fine on the same installation. I only had to install the chipset INF drivers, Ethernet and USB3 drivers. Most likely you didn't set up the SATA controller on the same mode (AHCI vs RAID vs IDE legacy).