Hi, I found your mobo specs even though yours doesn't have onboard video like mine does I have a MSI c45-770 based amd board similiar to yours.
Go to to AsRock official site:ASRock > Products > Motherboard > M3A770DE > Download
and download their official chipset drivers, bios upate they recommend and install those first.
While you have that going on, go to here:ATI Radeon
As soon the new chipset drivers are installed and the new bios has been updated, reboot.
Install the graphics card driver and make sure windows 7 unltimate fully recognizes the card and doesn't blue screen on you.
Every goes fine you should be able to play a few games if something does not install especially the 5770, come back here and let us know what happen.
If push comes to shove it might need to be RMA'd if it's messed up, but thats a pretty low chance of that happening.