The P7H55D-M EVO has 2 x PCI-E port and 1 x PCI port:
so unfortunately you cannot add any other PCI cards with your current configuration. What other card do you want to add?
OK so we've confirmed that you have a SATA 6 HDD and it's connected to the SATA 6 port of the motherboard. Either this could be a BIOS setting or the SATA cable itself.
First, let's try the first bullet point from the following:
Let us know how you get on.
You can refer to this page in...